Sherloc: a comprehensive refinement of the ACMG-AMP variant classification criteria

Replication stress, microcephalic primordial dwarfism, and compromised immunity in ATRIP deficient patients

Ataxia telangiectasia and Rad3-related (ATR) kinase and its interacting protein ATRIP orchestrate the replication stress response. Homozygous splice variants in the ATRIP gene, resulting in ATRIP deficiency, were identified in two patients of independent ancestry with microcephaly, primordial dwarfism, and recurrent infections. The c.829+5G>T patient exhibited lymphopenia, poor vaccine responses, autoimmune features with hemolytic anemia, and neutropenia. Immunophenotyping revealed reduced CD16+/CD56dim NK cells and absent naïve T cells, MAIT cells, and iNKT cells. Lymphocytic defects were characterized by TCR oligoclonality, abnormal class switch recombination, and impaired T cell proliferation. ATRIP deficiency resulted in low-grade ATR activation but impaired CHK1 phosphorylation under genotoxic stress. ATRIP-deficient cells inadequately regulated DNA replication, leading to chromosomal instability, compromised cell cycle control, and impaired cell viability. CRISPR-SelectTIME confirmed reduced cell fitness for both variants. This study establishes ATRIP deficiency as a monogenic cause of microcephalic primordial dwarfism, highlights ATRIP's critical role in protecting immune cells from replication stress, and offers new insights into its canonical functions.

Harnessing genotype and phenotype data for population-scale variant classification using large language models and bayesian inference

Variants of Uncertain Significance (VUS) in genetic testing for hereditary diseases burden patients and clinicians, yet clinical data that could reduce VUS are underutilized due to a lack of scalable strategies. We assessed whether a machine learning approach using genotype and phenotype data could improve variant classification and reduce VUS. In this cohort study of a multi-step machine learning approach, patient data from test requisition forms were used to distinguish patients with molecular diagnoses from controls ("patient score"). A generative Bayesian model then used patient scores and variant classifications to infer variant pathogenicity ("variant score"). The study included 3.5 million patients referred for clinical genetic testing across various conditions. Primary outcomes were model- and gene-level discrimination, classification performance, probabilistic calibration, and concordance with orthogonal pathogenicity measures. Integration into a semi-quantitative classification framework was based on posterior pathogenicity probabilities matching PPV ≥ 0.99/NPV ≥ 0.95 thresholds, followed by expert review. We generated 1,334 clinical variant models (CVMs); 595 showed high performance in both machine learning steps (AUROCpatient ≥ 0.8 and AUROCvariant ≥ 0.8) on held-out data. High-confidence predictions from these CVMs provided evidence for 5,362 VUS observed in 200,174 patients, representing 23.4% of all VUS observations in these genes. In 17 frequently tested genes, CVMs reclassified over 1,000 unique VUS, reducing VUS report rates by 9-49% per condition. In conclusion, a scalable machine learning approach using underutilized clinical data improved variant classification and reduced VUS.

Reclassifying NOBOX variants in primary ovarian insufficiency cases with a corrected gene model and a novel quantitative framework

STUDY QUESTION

How updated expression and genomic data combined with a disease/disorder-specific classification system can be used to correct a gene model for a better evaluation of the pathogenicity of variants found in patients?

SUMMARY ANSWER

By combining available genomic and transcriptomic data from several species and a quantitative classification framework with primary ovarian insufficiency (POI)-adjusted parameters, we correct the human NOBOX (newborn ovary homeobox) gene model and provide a reclassification of variants previously reported in POI cases.

WHAT IS KNOWN ALREADY

The NOBOX gene, encoding a gonad-specific transcription factor with a crucial role in early folliculogenesis and considered a major gene involved in POI, is currently described as being expressed as four transcripts, the longest one considered canonical. All the variants identified in POI cases have been evaluated according to this canonical transcript, and the various functional tests have been performed using the corresponding predicted protein.

STUDY DESIGN, SIZE, DURATION

We refined and corrected the NOBOX gene model using available genomic and RNAseq data in human and 16 other mammalian species. Expression data were selected for tissue specificity, strand specificity, and coverage. The analysis of RNAseq data from different ovarian fetal stages allows for a time-course description of NOBOX isoforms. Literature was scanned to retrieve NOBOX variants reported in POI cases, and NOBOX variants present in ClinVar and GnomAD 4 databases were also retrieved.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Strand-specific RNAseq data from human fetal ovaries and human adult testes were analysed to infer the correct human NOBOX gene isoforms. The conservation of the gene structure was verified by combining the aligned genomic sequences from 17 mammalian species covering a wide phylogenetic range and the relevant RNAseq data. As changing a gene model implies a reclassification of variants, we set up a quantitative framework with updated variant frequencies from GnomAD4 and POI-adjusted parameters following the American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines. Using this framework, we reclassified 44 NOBOX variants reported in POI patients and families, 117 NOBOX variants reported in ClinVar, and 2613 NOBOX variants present in GnomAD4.

MAIN RESULTS AND THE ROLE OF CHANCE

The corrected NOBOX gene model proposes the invalidation of two transcripts, including the canonical one. The two correct isoforms were present in fetal ovarian samples, and only one was detected in adult testes. Only 14 variants remained as possibly causative for POI. Furthermore, this re-evaluation strongly suggests that NOBOX biallelic variants are the most likely cause of POI.

LARGE SCALE DATA

Large tables are provided as supplementary data sets on the Zenodo repository.

LIMITATIONS, REASONS FOR CAUTION

The proposed gene model is robust but relies on available transcriptomic data covering a range of time points and tissues. Our scoring system was manually adjusted and other laboratories can implement it with different parameters.

WIDER IMPLICATIONS OF THE FINDINGS

For the NOBOX variants that cannot be considered pathogenic or causative anymore, the genome/exome sequencing data of the corresponding patients should be reanalysed. Furthermore, the functional studies performed using the obsolete coding sequence should be reconsidered. The corrected gene model should be taken into account when evaluating novel NOBOX variants identified in POI patients. Our results highlight the importance of the careful assessment of the most updated expression data for validating a gene model, enabling a correct evaluation of the pathogenicity of variants found in patients. The proposed quantitative framework developed here can be used for the classification of variants in other genes underlying POI. Furthermore, the global approach based on quantitatively adjusting the ACMG/AMP guidelines could be extended to other inherited pathologies.

STUDY FUNDING/COMPETING INTEREST(S)

This project was not funded. All the authors have no conflict of interest to disclose.

Deep learning tools predict variants in disordered regions with lower sensitivity

BACKGROUND

The recent AI breakthrough of AlphaFold2 has revolutionized 3D protein structural modeling, proving crucial for protein design and variant effects prediction. However, intrinsically disordered regions-known for their lack of well-defined structure and lower sequence conservation-often yield low-confidence models. The latest Variant Effect Predictor (VEP), AlphaMissense, leverages AlphaFold2 models, achieving over 90% sensitivity and specificity in predicting variant effects. However, the effectiveness of tools for variants in disordered regions, which account for 30% of the human proteome, remains unclear.

RESULTS

In this study, we found that predicting pathogenicity for variants in disordered regions is less accurate than in ordered regions, particularly for mutations at the first N-Methionine site. Investigations into the efficacy of variant effect predictors on intrinsically disordered regions (IDRs) indicated that mutations in IDRs are predicted with lower sensitivity and the gap between sensitivity and specificity is largest in disordered regions, especially for AlphaMissense and VARITY.

CONCLUSIONS

The prevalence of IDRs within the human proteome, coupled with the increasing repertoire of biological functions they are known to perform, necessitated an investigation into the efficacy of state-of-the-art VEPs on such regions. This analysis revealed their consistently reduced sensitivity and differing prediction performance profile to ordered regions, indicating that new IDR-specific features and paradigms are needed to accurately classify disease mutations within those regions.

Application of genetic testing criteria for hereditary breast cancer in South Africa

PURPOSE

Breast cancer (BC) is the commonest cancer in South African women. A proportion are associated with a pathogenic or likely pathogenic (P/LP) variant in a BC susceptibility gene. Clinical guidelines for genetic testing are used to optimise variant detection while containing costs. We assessed the detection rate in women of diverse ancestries who met the South African National Department of Health (NDOH) testing guidelines, and analysed relationships between testing criteria, participant characteristics and presence of a BRCA1/2 P/LP variant.

METHODS

Records from 376 women with BC who met NDOH criteria and had genetic testing were included. Demographic, clinical and test result data were collated to describe detection rates according to criteria met, and a multivariate analysis conducted to find variables most frequently associated with a P/LP variant.

RESULTS

P/LP variant prevalence in women meeting NDOH testing criteria was 19.9% (75/376). Women meeting ≥ 2 guideline criteria were over twice as likely to have a P/LP variant (OR 2.27, 95%CI 1.27-4.07, p = 0.006), highlighting the guidelines' capacity to stratify risk. Family history (OR 1.97; 95%CI 1.05-3.70, p = 0.03) and Black African ancestry (OR 2.58; 95%CI 1.28-5.18, p < 0.01) were independently associated with having a BRCA1/2 P/LP variant when controlling for other variables. Notably, although Black African participants were less likely to report a family history, those that did had higher odds of a P/LP variant in BRCA1/2.

CONCLUSION

These results demonstrate the usefulness of the NDOH guidelines in women of diverse ancestries and provide insight into the factors associated with P/LP variants in understudied African populations.

Functional study of three cases with novel TBX19 variants

PURPOSE

Congenital isolated adrenocorticotropic hormone deficiency (CIAD) is an autosomal recessive disorder. This study identifies novel TBX19 variants for CIAD patients, explores its possible effect mechanism at the structural, functional and protein levels, and guides clinicians better understand the condition.

METHODS

The clinical characteristics of three CIAD children were summarized. Multiple sequence alignment was performed and five algorithms, PROVEA, PolyPhen2, Mutation Taster, FATHMM, and I Mutant2.0, were used for the pathogenicity prediction. In addition, the three-dimensional protein structure of wild-type TBX19 was generated by Alphafold 3 and its variants were shown using PyMOL. Furthermore, immunoblotting analysis was applied to examine changes in the protein levels and the luciferase reporter assay was performed to further investigate the effects of TBX19 and its variants on pro-opiomelanocortin (POMC) transcriptional activity.

RESULTS

We describe three Chinese patients with CIAD caused by TBX19 variants. The TBX19 variant, c.856C>T (p.R286*) was classified as pathogenic according to ACMG, whereas the other four variants, c.377C>T (p.P126L), c.602A>T (p.E201V), c.401A>G (p.H134R) and c.299G>A (p.R100H) were predicted to be disease-causing. Variants lead to alter interactions, conformational changes in proteins or truncate protein. TBX19 and PITX1 cooperated, resulting in a strong synergistic activation effect on POMC transcriptional expression. A functional study showed that the variants in our study result in a significant suppression of POMC transcriptional activity compared to wild-type TBX19.

CONCLUSIONS

Our study identifies five TBX19 loss-of-function variants, two of which are novel and that provides new perspectives into the pathophysiological mechanism and expands the variant spectrum in IAD.

Mismatch Repair Proficient Colorectal Adenocarcinoma in Two Patients With Lynch Syndrome

Screening for Lynch syndrome (LS) is essential in colorectal carcinoma (CRC) diagnosis. The hallmark of CRC in LS is mismatch repair (MMR) deficiency, a vital biomarkers assessed by microsatellite instability (MSI) analysis and/or immunohistochemistry (IHC) staining of the MMR proteins in the tumor, that also predict response to immune checkpoint inhibitors. We report two LS patients who developed MMR proficient CRCs. Patient A, with a pathogenic MSH6 germline variant, presented with two MMR discordant CRCs: a rectal MMRd/MSI adenocarcinoma, and a sigmoid MMR proficient (MMRp) and microsatellite stable (MSS) adenocarcinoma, leading to metastasis. While the MMRd/MSI carcinoma was recognized early and showed complete pathologic response after pembrolizumab treatment, the MMRp/MSS adenocarcinoma was underrecognized and poorly responsive to treatment. A second patient, with a pathogenic PMS2 variant, also developed a MMRp CRC. These cases highlight the complex biological pathways in CRC development and the impact of molecular classification on treatment.

Analysis of TTN Truncating Variants in >74 000 Cases Reveals New Clinically Relevant Gene Regions

BACKGROUND

Truncating variants (TTNtvs) in the titin (TTN) gene have been associated with cardiomyopathies or arrhythmias (C/A) and autosomal recessive neuromuscular diseases (NM). However, the clinical significance of TTNtvs across the entire coding sequence of TTN has not been comprehensively assessed. The purpose of this study was to examine the burden of TTNtvs in C/A and NM cases compared with controls in the genome aggregation database.

METHODS

This was a retrospective study of probands who underwent multigene testing (49 740 C/A panel, 24 514 NM panel) that included TTN from November 2017 to October 2021. Burden testing was performed using controls in the genome aggregation database v3.1.2 database, and the analysis was stratified by exon/band location and exon usage in cardiac or skeletal muscle. Frequency and odds ratio of TTNtv alleles in C/A or NM cases and genome aggregation database controls were measured.

RESULTS

There were 2446 (4.9%) C/A and 482 (2.0%) NM cases with 2446 and 528 TTNtv alleles, respectively. TTNtvs in all bands were significantly enriched in both C/A and NM cases compared with controls. A significant enrichment of TTNtvs in C/A was observed for exon 358 of the M-band (odds ratio, 2.55 [95% CI, 1.85-3.54]) but not the other M-band exons.

CONCLUSIONS

In the largest single-site cohort of C/A and NM cases with TTNtvs, an enrichment of TTNtvs across TTN was observed. These findings expand the clinically relevant regions of TTN.

RORA-neurodevelopmental disorder: A unique triad of developmental disabilities, cerebellar anomalies, and myoclonic seizures

PURPOSE

RORA encodes the RAR-related orphan receptor-α, playing a pivotal role in cerebellar maturation and function. Here, we report the largest series of individuals with RORA-related-neurodevelopmental disorder.

METHODS

Forty individuals (30 unrelated; 10 siblings from 4 families) carrying RORA pathogenic/likely pathogenic variants were collected through an international collaboration.

RESULTS

The 33 variants (29 de novo, 4 inherited, and 1 shared), identified by genome/exome sequencing (n = 21), chromosomal microarray analysis (n = 7), or gene panels (n = 4), included frameshift (n = 18/33), missense (n = 9/33), and stop codon (n = 6/33). Developmental disability (n = 32/37), intellectual disability (n = 22/32), and cerebellar signs (n = 25/34) were the most striking clinical features. Cerebellar symptoms were divided into early-onset, late-onset, and progressive subgroups. Cerebellar hypoplasia, atrophy, or both (n = 16/25) were more frequent in individuals with missense variants in the DNA-binding domain. Epilepsy (n = 18/38), with prominent myoclonic seizure types (n = 11/18), was classified in (1) genetic generalized epilepsy (n = 10/18) with a syndromic diagnosis identifiable for 6: epilepsy with eyelid myoclonia (n = 5/6) and epilepsy with myoclonic absence (n = 1/6); (2) developmental and epileptic encephalopathy (n = 5/18); and (3) unclassified (n = 3/18). A participant with rapid deterioration of visual acuity and cone/rod dystrophy was reported.

CONCLUSION

Missense variants in DNA-binding domain correlate to a more severe cerebellar phenotype. The RORA-related-neurodevelopmental disorder triad comprises developmental disability, cerebellar features, and a spectrum of myoclonic epilepsy.

Biallelic SCN1A variants with divergent epilepsy phenotypes

PURPOSE

Pathogenic SCN1A variants most commonly cause autosomal dominant Dravet syndrome and genetic epilepsy with febrile seizures plus (GEFS+). However, rare homozygous SCN1A variants have also been reported. We report two new cases of homozygous SCN1A variants associated with divergent epilepsy phenotypes.

METHODS

We retrospectively reviewed the charts of two unrelated patients with different homozygous SCN1A variants. We also reviewed all published cases of biallelic SCN1A pathogenic variants, focusing on the epilepsy phenotypes.

RESULTS

Patient 1 had a homozygous c. 1676T>A, (p. Ile559Asn) variant of uncertain significance, inherited from asymptomatic parents. Patient 1 exhibited early afebrile seizures controlled by first-line anti-seizure medications and no febrile seizures or status epilepticus, as well as profound developmental delay, macrocephaly, and mild dysmorphic features. Patient 2 had a homozygous pathogenic c. 4970G>A, (p. Arg1657His) variant carried by asymptomatic parents. This patient presented with early, recurrent, and prolonged febrile seizures, moderate developmental delay, and motor dysfunction and was diagnosed with Dravet syndrome. We identified 16 further cases from the literature. Including our cases, 9/18 (50 %) were diagnosed with Dravet syndrome and 6/18 (33 %) with GEFS+. The mean age of seizure onset was 7 months (range 3-19 months). Phenotypes ranged from intact neurodevelopment with controlled epilepsy to profound developmental delay and refractory epilepsy.

CONCLUSION

These cases highlight and expand the phenotypic spectrum associated with biallelic SCN1A variants. While some patients present typically for Dravet/GEFS+, others may present with developmental delay in the absence of febrile seizures or status epilepticus. Further studies are needed to confirm genotype-phenotype relationships.

The current landscape of clinical exome and genome reanalysis in the U.S

The majority of patients undergoing exome or genome sequencing receive a nondiagnostic result. Periodic reanalysis is known to increase diagnostic yield from exome sequencing, yet laboratory reanalysis practices are obscure. We sought to define the landscape of exome and genome reanalysis across clinical laboratories. Genetic testing registries were queried to identify eligible clinical genetic laboratories offering exome and/or genome sequencing in the United States. A survey administered to lab representatives investigated reanalysis offerings, policies, perceived uptake, bioinformatic steps, and billing options. The analysis consisted of descriptive statistics. Survey data were collected from 30 of 32 eligible laboratories (93%), comprising 28 exome products and 13 genome products. Reanalysis was widely available for both exomes (n = 27/28, 96%) and genomes (n = 12/13, 92%). Most participating laboratories required ordering providers to initiate reanalysis (n = 24/28, 86%). Most respondents estimated providers initiated reanalysis in less than 10% of all exomes (n = 12/22) or genomes (n = 6/9) sequenced. The approach to reanalysis varied greatly by laboratory. Laboratory approaches to exome and genome reanalysis are highly variable and typically require provider initiation. This could contribute to low reanalysis uptake and increased administrative burden on providers. Further work should emphasize development of clinical exome and genome reanalysis standards.

Identification and functional validation of a novel FBN1 variant in a Marfan syndrome family using a zebrafish model

BACKGROUND

Marfan syndrome (MFS) is an inherited autosomal dominant disorder that affects connective tissue with an incidence of about 1 in 5,000 to 10,000 people. 90% of MFS is caused by mutations in the fibrillin-1 (FBN1) gene. We recruited a family with MFS phenotype in South China and identified a novel variant. This study investigated whether this genetic variant is pathogenic and the potential pathway related to lipid metabolism in MFS.

METHODS

A three-generation consanguineous family was recruited for this study. Whole exome sequencing (WES) was utilized on family members. The 3D structure of the protein was predicted using AlphaFold. CRISPR/Cas9 was applied to generate a similar fbn1 nonsense mutation (fbn1+/-) in zebrafish. RNA-seq analysis on zebrafish was performed to identify potential pathways related to MFS pathogenesis.

RESULTS

Our study identified a novel variant [NM_000138.5; c.7764 C > G: p.(Y2588*)] in FBN1 gene from the family and identified the same site mutation among the proband along with her son and daughter. Structural modeling showed the p.Y2588* mutation resulted from a truncated protein. Compared to wild-type zebrafish, the F2 generation fbn1+/- zebrafish exhibited MFS phenotype. RNA-seq analysis indicated that many genes related to leptin are up-regulating, which could affect bone development and adipose homeostasis.

CONCLUSION

A novel variant was identified in FBN1 gene. In a zebrafish model, we found functional evidence supporting the pathogenicity of the detected nonsense mutation. Our research proposes a possible mechanism underlying the relationship between lipid metabolism and MFS. These findings can help improve the clinical diagnosis and treatment of MFS.

Impact of ASXL1 Gene Alterations on Myelodysplastic Syndrome With Isolated 20q Deletion

BACKGROUND

Isolated 20q deletion [del(20q)] is a recurrent favorable abnormality in myelodysplastic syndrome (MDS) and may cause deletion of the ASXL1 gene. Meanwhile, ASXL1 mutations are also common in individuals with MDS. This study aimed to describe the biological and clinical implications of ASXL1 mutations and deletion in newly diagnosed MDS patients with isolated del(20q).

METHODS

Gene mutation and copy number alterations in 178 newly diagnosed MDS patients with isolated del(20q) were analyzed using DNA next generation sequencing.

RESULTS

Twenty-five (14%) of 178 patients were found to have ASXL1 mutations, which exhibited lower absolute neutrophil counts (ANC) (p = 0.006), a higher percentage of bone marrow blasts (p = 0.001), more mutant genes (p < 0.001), higher IPSS-R (p = 0.038) and IPSS-M (p = 0.001) risk groups. Furthermore, ASXL1 mutations were preferentially associated with mutations in U2AF1, and most ASXL1 mutations (68%) were observed as subclonal lesions. ASXL1 frameshift mutations were associated with a worse prognosis in MDS patients with low blasts (MDS-LB) (p = 0.043), but not in those with increased blasts (MDS-IB). Twenty-two (26.8%) of 82 patients were found to have ASXL1 deletion, which exhibited a lower IPSS-M risk group, lower platelet counts, higher ANC levels, and higher hemoglobin levels compared to ASXL1 patientsonly-mut and ASXL1wt patients. Two (2.4%) of the 82 patients exhibited biallelic ASXL1 inactivation (ASXL1mut&del).

CONCLUSIONS

ASXL1 mutations are one of the late genetic events in MDS patients with isolated 20q deletion, and different types of ASXL1 gene alterations have distinct clinical and biological characteristics.

A 59-Year-Old Man with Fatigue and Abdominal Pain

AbstractMorning Report is a time-honored tradition where physicians-in-training present cases to their colleagues and clinical experts to collaboratively examine an interesting patient presentation. The Morning Report section seeks to carry on this tradition by presenting a patient's chief concern and story, inviting the reader to develop a differential diagnosis and discover the diagnosis alongside the authors of the case. This report examines the story of a 59-year-old man with a history of nephrolithiasis and gastroesophageal reflux who sought evaluation for fatigue and abdominal pain. Using questions, physical examination, and testing, an illness script for the presentation emerges. As the clinical course progresses, the differential is iteratively refined until a final diagnosis is made.

Markedly Elevated Citrulline in a Neonate: Citrin Deficiency due to a Previously Unreported Solute Carrier Family 25 Member 13 Variant

BACKGROUND

Citrin deficiency (CD) is an autosomal recessive metabolic disorder affecting the urea cycle and energy production. Diagnosis involves measuring ammonia and amino acid levels (eg: citrulline), with confirmation through solute carrier family 25 member 13 (SLC25A13) gene mutation analysis. Herein, we present a case report of a variant in the SLC25A13 gene that has not been previously reported in the literature.

CASE REPORT AND RESULTS

The subject was a full-term Hispanic girl infant who was provisionally diagnosed with amino aciduria/urea cycle disorder with citrullinemia of unidentified type based on the second newborn screen performed at the 10th day of life. Sequence analysis and deletion/duplication testing using a panel consisting of 5 genes pertaining to citrullinemia revealed the patient carried a frameshift variant in the SLC25A13 gene (c.429_430del; pArg144fs) consistent with elevated citrulline results. The variant is not found in population databases (gnomAD). While ClinVar has only one entry for this variant (Variation ID: 1076508) and classifies it as pathogenic/likely pathogenic, no case report association exists between this variant and citrullinemia/CD or any SLC25A13-related conditions.

CONCLUSION

This case study expands the CD variant spectrum and describes a frameshift variant in the SLC25A13 gene in a patient linked to pathology. The finding emphasizes the importance of integrating clinical features with biochemical and genetic analysis to better understand genotype-phenotype correlations in CD and improve management strategies.

Calibrated Functional Data Decreases Clinical Uncertainty for Tier 1 Monogenic Disease: Application to Long QT Syndrome

Rare missense variants are often classified as variants of uncertain significance (VUS) due to insufficient evidence for classification. These ambiguous findings create anxiety and frequently lead to inappropriate workup, colloquially referred to as the 'diagnostic odyssey'. Well-validated high-throughput experimental data have the potential to significantly reduce the number of VUS identified by clinical genetic testing, though the extent of this reduction and the optimal strategies to achieve it remain unclear.1.

Clinical characteristics of EGFR-ctDNA shedders in EGFR-mutant NSCLC patients

BACKGROUND

Circulating tumor DNA (ctDNA) revolutionized the molecular diagnostics of lung cancer by enabling non-invasive, sensitive identification of actionable mutations. However, ctDNA analysis may be challenging due to tumor shedding variability, leading to false negative results. This study aims to understand the determinants for ctDNA shedding based on clinical characteristics of lung cancer patients, for a better interpretation of false negative results to be considered when ordering ctDNA analysis for clinical practice.

METHODS

Blood samples were collected from patients with stage IV EGFR-mutated (mEGFR) NSCLC before treatment and monitored until disease progression. EGFR was assessed on tissue by standard procedures, while EGFR status on ctDNA was tested using dPCR at baseline and at the first reassessment. NGS was used to evaluate patients mutational status at the progression of the disease.

RESULTS

A total of 40 mEGFR tissue samples were collected. Plasma samples were analyzed for mEGFR before starting the first line, 65 % of patients had detectable mEGFR in ctDNA ("shedders"). Higher ECOG PS (p = 0.04), bilateral localization of primary tumor (p = 0.04), and the presence of intrathoracic/extrathoracic disease (p = 0.05), were associated to mEGFR shedding. Shedders had shorter PFS compared to non-shedders (p = 0.03). Patients with detectable mEGFR in ctDNA at the first radiological assessment exhibited worse PFS compared to patients with ctDNA clearance (p = 0.05).

CONCLUSION

Our preliminary data demonstrate that specific clinical characteristics predict mEGFR shedding in ctDNA of NSCLC, suggesting a potential clinical applicability for understanding potential false negative results and appropriate reporting in clinical practice.

Multiethnic prevalence of the APOL1 G1 and G2 variants among the Israeli dialysis population

Background and hypothesis

The two apolipoprotein L1 (APOL1) variants, G1 and G2, are common in populations of sub-Saharan African ancestry. Individuals with two of these alleles (G1 or G2) have an increased risk for a spectrum of non-diabetic chronic kidney diseases. However, these variants are typically not observed outside of populations that self-identify as current continental Africans or having clear recent African ancestry such as, most notably, African Americans, and other large population groups in the Americas and several European countries. We hypothesized that the diverse ethnic groups within the Israeli population may exhibit varying levels of recent African ancestry. Therefore, it is plausible that APOL1 risk alleles might be present even in individuals who do not self-identify as being of sub-Saharan African descent.

Methods

We non-selectively screened people with kidney failure across Israel for APOL1 risk variants using restriction fragment length polymorphism.

Results

We recruited 1744 individuals from 38 dialysis units in Israel. We identified eight patients of Moroccan Jewish, Bedouin, or Muslim Arab ancestry, who carry at least one G1 or G2 allele. None of the eight patients carried the protective APOL1 p.N264K variant. Furthermore, despite all Bedouin individuals being G2 heterozygous, the G2 minor allele frequency was significantly enriched in kidney failure cases compared to ethnically matched controls (P = .006).

Conclusions

These findings show that APOL1 G1 and G2 allelic variants are present in populations previously not appreciated to possess recent sub-Saharan ancestry and suggest that a single G2 risk variant may confer increased risk for chronic kidney disease in certain population contexts.

Infantile epileptic spasms syndrome: an etiologic study of 361 patients with infantile epileptic spasms syndrome

Introduction

Infantile Epileptic Spasms Syndrome (IESS) typically has a profound impact on the neurodevelopment of patients. The study on IESS indicates possible geographical variation in etiology and a lack of data from China. Our study intends to summarize the etiology of IESS and analyze its characteristics.

Methods

A retrospective analysis was performed to gather clinical data from patients diagnosed with IESS at the Department of Neurology of Qilu Hospital of Shandong University and the Children's Hospital Affiliated to Shandong University between June 2017 to May 2024.

Results

A total of 361 patients with IESS were included, comprising 115 structural cases (31.9%), 37 genetic cases (10.2%), 32 genetic-structural cases (8.9%), 9 metabolic cases (2.5%), 3 infectious cases (0.8%), and 165 cases with unknown etiology (45.7%). No immunological cause was determined. The primary cause of the condition was linked to hypoxic-ischemic encephalopathy (HIE), with structural brain abnormalities following closely. The predominant pathogenic genes identified were TSC2, NF1, SCN8A, and KCNQ2. Male gender, preterm infants, low birth weight infants, and developmental regression in patients were associated with a higher likelihood of structural etiology. Patients exhibiting developmental regression before the commencement demonstrated inferior outcomes. Patients administered adrenocorticotropic hormone (ACTH) exhibited a higher likelihood of attaining seizure control, and those who responded favorably to the medication saw improved results.

Conclusion

The predominant etiology of IESS is structural, succeeded by genetic factors, with significant pathogenic genes comprising TSC2, NF1, SCN8A, and KCNQ2. The genetic classifications exhibit geographic variability. Genetic and structural etiologies are frequently linked to an unfavorable prognosis. Genetic testing can help clarify the etiology of IESS when metabolic screening and brain MRI results are negative. The advancement of genetic testing is crucial for future targeted and individualized diagnosis and therapy.

Mutational spectrum and deep phenotyping in Pseudoxanthoma Elasticum: Findings from a Portuguese cohort

INTRODUCTION

Pseudoxanthoma Elasticum (PXE) is a rare autosomal recessive disorder originated by disease-causing variants in ABCC6 gene. The purpose of this study was to characterize the genetic landscape, phenotypic spectrum and genotype-phenotype correlations in a Portuguese cohort of PXE patients.

METHODS

Multicentric cross-sectional study conducted in patients with a clinical and genetic diagnosis of PXE. Patients were identified using the IRD-PT registry (www.retina.com.pt). Genotypes were classified into 3 groups: (1) two truncating variants, (2) two non-truncating variants, or (3) mixed variants. Deep phenotyping comprised a comprehensive ophthalmologic and systemic evaluation using the updated Phenodex Score (PS).

RESULTS

Twenty-seven patients (23 families) were included. Sixteen different ABCC6 variants were identified, 7 of which are novel. The most prevalent variant was the nonsense variant c.3421C > T p.(Arg1141*) with an allele frequency of 18.5%. All patients exhibited ocular manifestations. Cutaneous manifestations were present in most patients (88.9%, n = 24/27). A PS score > E2 was strongly associated with worse visual acuity (B = -29.02; p = 0.001). No association was found between genotypic groups and cutaneous, vascular or cardiac manifestations.

CONCLUSIONS

This study describes the genetic spectrum of patients with PXE for the first time in a Portuguese cohort. A total of 16 different variants in ABCC6 were found (7 of which are novel), thus highlighting the genotypic heterogeneity associated with this condition and expanding its mutational spectrum. Still, no major genotype-phenotype associations could be established.

Novel KCNQ2 Variants Related to a Variable Phenotypic Spectrum Ranging from Epilepsy with Auditory Features to Severe Developmental and Epileptic Encephalopathies

Pathogenic KCNQ2 variants are associated with neonatal epilepsies, ranging from self-limited neonatal epilepsy to KCNQ2-developmental and epileptic encephalopathy (DEE). In this study, next-generation sequencing was performed, applying a panel of 142 epilepsy genes on three unrelated individuals and affected family members, showing a wide variability in the epileptic spectrum. The genetic analysis revealed two likely pathogenic missense variants (c.1378G>A and c.2251T>G) and the already-reported pathogenic splice site (c.1631+1G>A) in KCNQ2 (HGNC:6296). The phenotypes observed in the affected members of family 1, which shared the c.2251T>G variant, were epilepsy with auditory features (EAFs), focal epilepsy, and generalized epilepsy, and none of them suffered from neonatal seizures. The gene panel contained further genes related to EAFs (LGI1, RELN, SCN1A, and DEPDC5), which were tested with negative results. The phenotypes observed in family 2 members, sharing the splice site variant, were neonatal seizures and focal epilepsy in childhood. The last unrelated proband, harboring the de novo missense c.1378G>A, presented a clinical phenotype consistent with DEE. In conclusion, we identified two unreported KCNQ2 variants, and report a proband with EAFs and individuals without typical KCNQ2 neonatal seizures. Our study underscores the extreme variability in the phenotypic spectrum of KCNQ2-related epilepsies and unveils the prospect of its inclusion in screening panels for EAFs.

IDENTIFICATION OF CLINICALLY RELEVANT GENE VARIANTS IN COLON ADENOCARCINOMA SAMPLES OF UKRAINIAN PATIENTS USING A COMPREHENSIVE CANCER PANEL: A PILOT STUDY

The study aimed to identify the clinically relevant gene variants in colon adenocarcinoma samples of Ukrainian patients using the NGS Comprehensive Cancer Panel (CCP) to implement them conveniently in clinical practice.

METHODS

We have studied 20 samples of Ukrainian patients with colorectal adenocarcinomas of various differentiation grades. To identify the clinically relevant gene variants, the CCP data were filtered using the Franklin by Genoox database.

RESULTS

A total of 79 clinically relevant gene variant alterations (SNVs, INDELs) were found in 28 of 409 genes. The largest number of mutations was found in 3 genes, APC, TP53, and KRAS (16, 14, and 8, accordingly). We revealed 4 variants in PTEN and SMAD4, 3 variants in CHEK2, ERBB2, and PIK3CA genes, and 2 variants in AKT1, ATM, DST, IDH1, and TCF12. Mutations for 7 genes, KRAS, TP53, CHEK2, PTEN, AKT1, APC, and SMAD4, were found in more than 1 tumor tissue sample. Tier 1-2 gene variants rate was about 50% of all genetic variants. The therapeutic significance was found in more than 55% of mutations. Additionally, 11 novel genetic mutations in 9 genes have been identified, including G6PD, APC, DST, SINE1, SMAD2, and FLCN.

CONCLUSIONS

These data suggest a high level of clinical relevance of the NGS CCP approach. Further confirmation on a larger number of samples and using a deeper analysis by other approaches is required.

A missense variant effect map for the human tumor-suppressor protein CHK2

The tumor suppressor CHEK2 encodes the serine/threonine protein kinase CHK2 which, upon DNA damage, is important for pausing the cell cycle, initiating DNA repair, and inducing apoptosis. CHK2 phosphorylation of the tumor suppressor BRCA1 is also important for mitotic spindle assembly and chromosomal stability. Consistent with its cell-cycle checkpoint role, both germline and somatic variants in CHEK2 have been linked to breast and other cancers. Over 90% of clinical germline CHEK2 missense variants are classified as variants of uncertain significance, complicating diagnosis of CHK2-dependent cancer. We therefore sought to test the functional impact of all possible missense variants in CHK2. Using a scalable multiplexed assay based on the ability of human CHK2 to complement DNA sensitivity of Saccharomyces cerevisiae cells lacking the CHEK2 ortholog, RAD53, we generated a systematic "missense variant effect map" for CHEK2 missense variation. The map reflects known biochemical features of CHK2 while offering new biological insights. It also provides strong evidence toward pathogenicity for some clinical missense variants and supporting evidence toward benignity for others. Overall, this comprehensive missense variant effect map contributes to understanding of both known and yet-to-be-observed CHK2 variants.

Clonal landscape and clinical outcomes of telomere biology disorders: somatic rescue and cancer mutations

ABSTRACT

Telomere biology disorders (TBDs), caused by pathogenic germ line variants in telomere-related genes, present with multiorgan disease and a predisposition to cancer. Clonal hematopoiesis (CH) as a marker of cancer development and survival in TBDs is poorly understood. Here, we characterized the clonal landscape of a large cohort of 207 patients with TBD with a broad range of age and phenotype. CH occurred predominantly in symptomatic patients and in signature genes typically associated with cancers: PPM1D, POT1, TERT promoter (TERTp), U2AF1S34, and/or TP53. Chromosome 1q gain (Chr1q+) was the commonest karyotypic abnormality. Clinically, multiorgan involvement and CH in TERTp, TP53, and splicing factor genes were associated with poorer overall survival. Chr1q+ and splicing factor or TP53 mutations significantly increased the risk of hematologic malignancies, regardless of clonal burden. Chr1q+ and U2AF1S34 mutated clones were premalignant events associated with the secondary acquisition of mutations in genes related to hematologic malignancies. Similar to the known effects of Chr1q+ and TP53-CH, functional studies demonstrated that U2AF1S34 mutations primarily compensated for aberrant upregulation of TP53 and interferon pathways in telomere-dysfunctional hematopoietic stem cells, highlighting the TP53 pathway as a canonical route of malignancy in TBD. In contrast, somatic POT1/PPM1D/TERTp mutations had distinct trajectories unrelated to cancer development. With implications beyond TBD, our data show that telomere dysfunction is a strong selective pressure for CH. In TBD, CH is a poor prognostic marker associated with worse overall survival. The identification of key regulatory pathways that drive clonal transformation in TBD allows for the identification of patients at a higher risk of cancer development.

The role of genetic testing in adult patients with unexplained epilepsy

OBJECTIVE

Genetic causes are often overlooked in patients with epilepsy of unknown etiology, particularly in adults. We aimed to evaluate clinical features of genetic epilepsy and the utility of genetic testing.

METHODS

We retrospectively screened consecutive unrelated adult epilepsy patients at an epilepsy clinic from April 2022 to May 2023. Patients with unknown etiology or special brain lesions were classified as unexplained epilepsy. In them, patients with young-onset seizures or family history of seizures who were recommended for and ultimately underwent genetic testing using either panel next-generation sequencing (NGS) or whole-exome sequencing (WES) were enrolled. A definite or probable genetic diagnosis was established through genotype-phenotype correlation. We compared the demographic characteristics between genetic epilepsy and other etiologies.

RESULTS

Of the 374 adult epilepsy patients, 258 were classified as unexplained epilepsy, 129 were suspected of having genetic epilepsy due to young-onset seizures or a positive family history, 33 underwent genetic testing; 13 harbored variants classified as pathogenic, and 6 reached a definite genetic diagnosis, resulting in a yield of 18%. Among the 27 patients without a definite genetic diagnosis, 7 had a nongenetic structural etiology. Patients with genetic etiology exhibited greater multisystem involvement particularly multiple structural anomalies and early childhood-onset seizures, but wasn't directly correlated with young-onset seizures or a positive family history. The diagnostic yield was comparable between panel NGS and WES.

SIGNIFICANCE

In adult patients with unexplained epilepsy, genetic epilepsy is more associated with multisystem involvement and multiple structural anomalies but not family history of seizures or young-onset seizures.

Previously defined variants of uncertain significance may play an important role in epilepsy and interactions between certain variants may become pathogenic

OBJECTIVE

Epilepsy is a chronic neurological disorder related to various etiologies, and the prevalence of active epilepsy is estimated to be between 4 and 10 per 1000 individuals having a significant role in genetic mutations. Next-Generation Sequencing (NGS) panels are utilized for genetic testing, but a substantial proportion of the results remain uncertain and are not considered directly causative of epilepsy. This study aimed to reevaluate pediatric patients diagnosed with epilepsy who underwent genetic investigation using NGS panels, focusing on inconclusive variant findings or multiple variants of uncertain significance (VUSs).

METHODS

A subgroup of pediatric patients aged 0-25 years, diagnosed with epilepsy, who underwent genetic investigation with an NGS epilepsy panel at the Child Neurology Unit, The Edmond and Lily Safra Children's Hospital, Sheba Medical Center, between 2018 and 2022 through Invitae, was reevaluated. Patients with inconclusive variant findings or multiple VUSs in their test results were included. Genetic data were analyzed to identify potentially pathogenic variants and frequent genetic combinations.

RESULTS

Two unrelated potentially pathogenic variants were identified in the SCN9A and QARS1 genes. A frequent genetic combination, RANBP2&RYR3, was also observed among other combinations. The RANBP2 gene consistently co-occurred with RYR3 variants in uncertain results, suggesting potential pathogenicity. Analysis of unaffected parents' data revealed certain combinations inherited from different parents, suggesting specific gene combinations as possible risk factors for the disease.

SIGNIFICANCE

This study highlights the importance of reevaluating genetic data from pediatric epilepsy patients with inconclusive variant findings or multiple VUSs. Identification of potentially pathogenic variants and frequent genetic combinations, such as RANBP2&RYR3, could aid in understanding the genetic basis of epilepsy and identifying potential hotspots.

PLAIN LANGUAGE SUMMARY

We have performed a retrospective analysis on a subpopulation of pediatric patients diagnosed with epilepsy. We found that specific genetic variants were repeatable, indicating their potential pathogenicity to the disease.

Carrier frequency and incidence estimation of deficiency of adenosine deaminase 2 in the Chinese population based on massive exome sequencing data

Deficiency of adenosine deaminase 2 (DADA2) is an autosomal recessive autoinflammatory disease characterised by early onset stroke, recurrent fever, and diverse vascular pathologies, caused by loss-of-function homozygous or compound heterozygous variants of ADA2. This research aimed to determine the carrier frequency and expected incidence of DADA2 in China, using massive exome sequencing (ES) data. A total of 50 likely pathogenic/pathogenic variants (LP/PVs) were identified among 69,413 Chinese individuals, including 20 novel and rare variants (<0.0022 % allele frequency), expanding the known spectrum of PVs in ADA2. The overall carrier frequency in the Chinese population was 1.05 % (732/69,413) and the estimated incidence of DADA2 was approximately one in 92,251 individuals. The present study provides an accurate estimation of the prevalence of DADA2 in China, supporting genetic counseling, early diagnosis treatment, and prognostic evaluation.

Role of Genetic Testing in Kidney Stone Disease: A Narrative Review

PURPOSE OF REVIEW

Kidney stone disease (KSD) is a common and potentially life-threatening condition, and half of patients experience a repeat kidney stone episode within 5-10 years. Despite the ~50% estimate heritability of KSD, international guidelines have not kept up with the pace of discovery of genetic causes of KSD. The European Association of Urology guidelines lists 7 genetic causes of KSD as 'high risk'.

RECENT FINDINGS

There are currently 46 known monogenic (single gene) causes of kidney stone disease, with evidence of association in a further 23 genes. There is also evidence for polygenic risk of developing KSD. Evidence is lacking for recurrent disease, and only one genome wide association study has investigated this phenomenon, identifying two associated genes (SLC34A1 and TRPV5). However, in the absence of other evidence, patients with genetic predisposition to KSD should be treated as 'high risk'. Further studies are needed to characterize both monogenic and polygenic associations with recurrent disease, to allow for appropriate risk stratification. Durability of test result must be balanced against cost. This would enable retrospective analysis if no genetic cause was found initially. We recommend genetic testing using a gene panel for all children, adults < 25 years, and older patients who have factors associated with high risk disease within the context of a wider metabolic evaluation. Those with a genetic predisposition should be managed via a multi-disciplinary team approach including urologists, radiologists, nephrologists, clinical geneticists and chemical pathologists. This will enable appropriate follow-up, counselling and potentially prophylaxis.

Clinical application of whole-exome sequencing analysis in childhood epilepsy

The swift updates of public databases and advancements in next-generation sequencing (NGS) technologies have enhanced the genetic identification capacities of epilepsy clinics. This study aimed to evaluate the diagnostic efficacy of NGS in pediatric epilepsy patients as a whole and to present the data obtained in the whole exome sequence analysis. We enrolled 40 children with suspected childhood epilepsy in this study. All patients underwent evaluation by a clinical geneticist or pediatric neurologist and the molecular genetic analysis of those children was performed by whole-exome sequencing (WES). Out of the 40 patients, 12 (30%) received a genetic diagnosis, involving 14 mutations across 13 genes. The cumulative positive diagnostic yield was 30%. Twelve of these patients were identified to have 5 variants previously documented as pathogenic, 9 variants classified as likely pathogenic, and 5 novel variants that have not been reported before. The outcomes indicate that whole-exome sequencing offers great benefits in clinical patient diagnosis, particularly in terms of detecting diagnostic variants. This study underscored the significance of whole exome sequencing (WES) studies, where only a broad gene set is examined in epilepsy patients. This approach has the potential to establish gene-specific phenotypic profiles, particularly by uncovering novel candidate genes in epilepsy patients with well-defined phenotypes. Additionally, conducting validation studies on variants of uncertain clinical significance could enhance the outcome yield.

Genetics architecture of spontaneous coronary artery dissection in an Italian cohort

Spontaneous coronary artery dissection (SCAD) is a relevant non-atherosclerotic cause of acute coronary syndrome with a complex genetic architecture. Recent discoveries have highlighted the potential role of miRNAs and protein-coding genes involved in the processing of small RNAs in the pathogenesis of SCAD. Furthermore, there may be a connection between SCAD and the increased cardiovascular risk observed in fragile X premutation carriers as well as a correlation with pathogenetic variants in genes encoding for collagen and extracellular matrix, which are related to connective tissue disorders (CTDs). In our cohort of 15 Italian SCAD patients, a total of 37 rare variants were identified in 34 genes using whole exome sequencing (WES) and TRIO-WES analysis when both parents were available. Three likely pathogenic/pathogenetic variants were found in genes previously associated with SCAD and CTDs (COL3A1, COL1A2, and SMAD3) and 26 variants of uncertain significance in genes previously associated with SCAD and CTDs. TRIO-WES analysis revealed 7 de novo variants, 1 of which was found in a potential novel candidate gene (DROSHA). In addition, a premutation allele of 55 ± 2 CGG repeats in the promoter of the FMR1 gene was identified in two related SCAD patients by test for CGG-repeat expansions in the 5'-UTR of the FMR1 gene. Our findings suggest various potential mechanisms such as mRNA toxicity, miRNA regulation, alteration of collagen, and the extracellular matrix architecture, all of which could disrupt vascular homeostasis, and finally, WES and TRIO-WES have proven to be the most powerful approaches for characterizing the genetic background of SCAD.

Germline sequence variation in cancer genes in Rwandan breast and prostate cancer cases

Cancer genetic data from Sub-Saharan African (SSA) are limited. Patients with female breast (fBC), male breast (mBC), and prostate cancer (PC) in Rwanda underwent germline genetic testing and counseling. Demographic and disease-specific information was collected. A multi-cancer gene panel was used to identify germline Pathogenic Variants (PV) and Variants of Uncertain Significance (VUS). 400 patients (201 with BC and 199 with PC) were consented and recruited to the study. Data was available for 342 patients: 180 with BC (175 women and 5 men) and 162 men with PC. PV were observed in 18.3% fBC, 4.3% PC, and 20% mBC. BRCA2 was the most common PV. Among non-PV carriers, 65% had ≥1 VUS: 31.8% in PC and 33.6% in BC (female and male). Our findings highlight the need for germline genetic testing and counseling in cancer management in SSA.

RNA Splicing Aberrations in Hereditary Cancer: Insights from Turkish Patients

The process of RNA splicing is fundamental in contributing to proteomic diversity and regulating gene expression. Dysregulation of splicing is associated with various human disorders, including cancer. Through functional studies, this study sought to examine the potential impact of seven variants within six inherited cancer-related genes on RNA splicing patterns in Turkish cancer patients. Upon detecting variants using Next-Generation Sequencing (NGS), we used Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) and Sanger sequencing to elucidate the effects of these variants on splicing. Three of the seven variants demonstrated no discernible effect on RNA, while four exhibited pathogenic characteristics. Specifically, the variants APC c.532-1G>A rs1554072547, BRCA1c.4358-3A>G rs1567779966, BRCA2c.7436-1G>C rs81002830 and MSH3c.1897-1G>A rs1744149615 were identified as pathogenic, while the variants BLMc.4076+4T>G rs183176301, RB1c.2489+2T>C rs1555294636 and RB1c.1050-2A>G rs? were found to be benign from a splicing perspective. These findings highlight the importance of verifying the precise consequences of splice-site variants through experimental analysis, given their potential implications for genetic disorders and cancer predisposition. This research contributes to the understanding of splice-site variants in inherited cancer predisposition, particularly among Turkish cancer patients. It emphasizes the necessity for further exploration into the mechanisms and functional consequences of alternative splicing for potential therapeutic interventions in cancer.

Pathomechanisms of Monoallelic variants in TTN causing skeletal muscle disease

Pathogenic variants in the titin gene (TTN) are known to cause a wide range of cardiac and musculoskeletal disorders, with skeletal myopathy mostly attributed to biallelic variants. We identified monoallelic truncating variants (TTNtv), splice site or internal deletions in TTN in probands with mild, progressive axial and proximal weakness, with dilated cardiomyopathy frequently developing with age. These variants segregated in an autosomal dominant pattern in 7 out of 8 studied families. We investigated the impact of these variants on mRNA, protein levels, and skeletal muscle structure and function. Results reveal that nonsense-mediated decay likely prevents accumulation of harmful truncated protein in skeletal muscle in patients with TTNtvs. Splice variants and an out-of-frame deletion induce aberrant exon skipping, while an in-frame deletion produces shortened titin with intact N- and C-termini, resulting in disrupted sarcomeric structure. All variant types were associated with genome-wide changes in splicing patterns, which represent a hallmark of disease progression. Lastly, RNA-seq studies revealed that GDF11, a member of the TGF-β superfamily, is upregulated in diseased tissue, indicating that it might be a useful therapeutic target in skeletal muscle titinopathies.

Clinical Variant Reclassification in Hereditary Disease Genetic Testing

Importance

Because accurate and consistent classification of DNA sequence variants is fundamental to germline genetic testing, understanding patterns of initial variant classification (VC) and subsequent reclassification from large-scale, empirical data can help improve VC methods, promote equity among race, ethnicity, and ancestry (REA) groups, and provide insights to inform clinical practice.

Objectives

To measure the degree to which initial VCs met certainty thresholds set by professional guidelines and quantify the rates of, the factors associated with, and the impact of reclassification among more than 2 million variants.

Design, Setting, and Participants

This cohort study used clinical multigene panel and exome sequencing data from diagnostic testing for hereditary disorders, carrier screening, or preventive genetic screening from individuals for whom genetic testing was performed between January 1, 2015, and June 30, 2023.

Exposure

DNA variants were classified into 1 of 5 categories: benign, likely benign, variant of uncertain significance (VUS), likely pathogenic, or pathogenic.

Main Outcomes and Measures

The main outcomes were accuracy of classifications, rates and directions of reclassifications, evidence contributing to reclassifications, and their impact across different clinical areas and REA groups. One-way analysis of variance followed by post hoc pairwise Tukey honest significant difference tests were used to analyze differences among means, and pairwise Pearson χ2 tests with Bonferroni corrections were used to compare categorical variables among groups.

Results

The cohort comprised 3 272 035 individuals (median [range] age, 44 [0-89] years; 2 240 506 female [68.47%] and 1 030 729 male [31.50%]; 216 752 Black [6.62%]; 336 414 Hispanic [10.28%]; 1 804 273 White [55.14%]). Among 2 051 736 variants observed over 8 years in this cohort, 94 453 (4.60%) were reclassified. Some variants were reclassified more than once, resulting in 105 172 total reclassification events. The majority (64 752 events [61.65%]) were changes from VUS to either likely benign, benign, likely pathogenic, or pathogenic categories. An additional 37.66% of reclassifications (39 608 events) were gains in classification certainty to terminal categories (ie, likely benign to benign and likely pathogenic to pathogenic). Only a small fraction (663 events [0.63%]) moved toward less certainty, or very rarely (61 events [0.06%]) were classification reversals. When normalized by the number of individuals tested, VUS reclassification rates were higher among specific underrepresented REA populations (Ashkenazi Jewish, Asian, Black, Hispanic, Pacific Islander, and Sephardic Jewish). Approximately one-half of VUS reclassifications (37 074 of 64 840 events [57.18%]) resulted from improved use of data from computational modeling.

Conclusions and Relevance

In this cohort study of individuals undergoing genetic testing, the empirically estimated accuracy of pathogenic, likely pathogenic, benign, and likely benign classifications exceeded the certainty thresholds set by current VC guidelines, suggesting the need to reevaluate definitions of these classifications. The relative contribution of various strategies to resolve VUS, including emerging machine learning-based computational methods, RNA analysis, and cascade family testing, provides useful insights that can be applied toward further improving VC methods, reducing the rate of VUS, and generating more definitive results for patients.

Natural history of ENPP1 deficiency: Nationwide Turkish Cohort Study of autosomal-recessive hypophosphataemic rickets type 2

OBJECTIVE

Autosomal-recessive hypophosphataemic rickets type 2 (ARHR2) is a rare disease that is reported in survivors of generalized arterial calcification of infancy (GACI).

DESIGN, PATIENTS AND MEASUREMENT

The objective of this study was to characterize a multicenter paediatric cohort with ARHR2 due to ectonucleotide pyrophosphatase/phosphodiesterase family member 1 (ENPP1) deficiency and with a diagnosis of GACI or GACI-related findings. The clinical, biochemical and genetic characteristics of the patients were retrospectively retrieved.

RESULTS

We identified 18 patients from 13 families diagnosed with ARHR2. Fifteen of the patients had an ENPP1 variation confirmed with genetic analyses, and three were siblings of one of these patients, who had clinically diagnosed hypophosphataemic rickets (HRs) with the same presentation. From nine centres, 18 patients, of whom 12 (66.7%) were females, were included in the study. The mean age at diagnosis was 4.2 ± 2.2 (1.6-9) years. The most frequently reported clinical findings on admission were limb deformities (66.6%) and short stature (44.4%). At diagnosis, the mean height SD was -2.2 ± 1.3. Five of the patients were diagnosed with GACI in the neonatal period and treated with bisphosphonates. Other patients were initially diagnosed with ARHR2, but after the detection of a biallelic variant in the ENPP1 gene, it was understood that they previously had clinical findings associated with GACI. Three patients had hearing loss, and two had cervical fusion. After the treatment of HRs, one patient developed calcification, and one developed intimal proliferation.

CONCLUSION

ARHR2 represents one manifestation of ENPP1 deficiency that usually manifests later in life than GACI. The history of calcifications or comorbidities that might be associated with GACI will facilitate the diagnosis in patients with ARHR2, and patients receiving calcitriol and phosphate medication should be carefully monitored for signs of calcification or intimal proliferation.

Two Novel Variants in the CHRNA2 and SCN2A Genes in Italian Patients with Febrile Seizures

BACKGROUND

Febrile seizures (FSs) are the most common form of epilepsy in children aged between six months and five years. The exact cause is unknown, but several studies have demonstrated the importance of genetic predisposition, with increasing involvement of receptors and ion channels. The present study aims to identify novel pathogenic variants in Italian patients with FSs.

METHODS

We performed targeted panel sequencing in a cohort of 21 patients with FSs. In silico analysis was performed to predict the pathogenic role of the resulting variants.

RESULTS

We found two novel variants segregating in two families with FSs: c.1021C>G (p.Leu341Val) in the CHRNA2 gene and c.140A>G (p.Glu47Gly) in SCN2A.

CONCLUSIONS

The c.1021C>G (p.Leu341Val) variant leads to a codon change of highly conserved leucine to valine at position 341 and is located in segments M3 of the subunit, which is important for channel gating. The c.140A>G (p.Glu47Gly) variant causes a substitution of glutamic acid with glycine at position 47 of the protein, which is highly conserved across the species. Moreover, it is located in the N-terminal domain, a region commonly affected in ASD, which impacts the inactivation kinetics and voltage dependence of steady-state activation. Further analyses are needed to better explain the role of CHRNA2 and SCN2A in the development of febrile seizures.

Multi-Gene Panel Testing for Hereditary Cancer Predisposition Among Patients Sixty-Five Years and Above Diagnosed With Breast Cancer

Background

The availability and affordability of germline genetic testing (GGT) has resulted in a broader utilization in daily clinical practice. However, adherence to testing guidelines is low, especially among older patients, where testing is often not offered.

Methods

In this study, consecutive, newly diagnosed patients with breast cancer (BC) aged ≥ 65 years and eligible for GGT, as per the National Comprehensive Cancer Network (NCCN) guidelines (version 1, 2021), were invited to participate, from March 2021 to December 2022. Patients were offered a restricted (two- or 20-gene panel), or an expanded 84-gene panel.

Results

During the study period, 204 patients were enrolled. The mean (standard deviation (SD)) age at BC diagnosis was 70.5 (5.13) years, ranging 65 - 81 years. All patients were Arab and the majority were Jordanian. The majority (n = 188, 92.2%) had early-stage (stages I and II) disease. One hundred three (50.5%) patients were tested with a restricted two-gene (n = 13) or 20-gene (n = 90) panel, while the remaining 101 (49.5%) patients had an expanded 84-gene panel. Family history of close blood relative(s) with BC was the most common indication for testing (n = 110, 53.9%). Among the entire study cohort, 22 (10.8%) had pathogenic/likely pathogenic germline variants (PGVs) and another 97 (47.5%) had ≥ 1 variants of uncertain significance (VUS). PGV rates were significantly higher with the expanded panel (14.9%) compared to restricted testing (6.8%) (P = 0.032). Similarly, VUS rates were significantly higher with the expanded panel (64.4%) compared to the restricted panel (31.1%) (P < 0.001). The most prevalent genes with PGVs were BRCA1/2 (31.3% of all PGV-positive patients), CHEK2 (23.1%) and ATM (19.2%).

Conclusion

GGT should not be overlooked in older BC patients, as this study demonstrates that > 10% of patients have PGVs, largely in potentially actionable genes.

Expanding the Russian allele frequency reference via cross-laboratory data integration: insights from 7452 exome samples

Population allele frequency is crucially important for accurate interpretation of known and novel variants in medical genetics. Recently, several large allele frequency databases, such as the Genome Aggregation Database (gnomAD), have been created to serve as a global reference for such studies. However, frequencies of many rare alleles vary dramatically between populations, and population-specific allele frequency is often more informative than the global one. Many countries and regions, including Russia, remain poorly studied from the genetic perspective. Here, we report the first successful attempt to integrate genetic information between major medical genetic laboratories in Russia. We construct RUSeq, an open, large-scale reference set of genetic variants by analyzing 7452 exome samples collected in two major Russian cities-Moscow and St. Petersburg. An ∼10-fold increase in sample size compared to previous studies allowed us to characterize extensive genetic diversity within the admixed Russian population with contributions from several major ancestral groups. We highlight 51 known pathogenic variants that are overrepresented in Russia compared to other European countries. We also identify several dozen high-impact variants that are present in healthy donors despite being annotated as pathogenic in ClinVar and falling within genes associated with autosomal dominant disorders. The constructed database of genetic variant frequencies in Russia has been made available to the medical genetics community through a variant browser available at http://ruseq.ru.

Patterns and Frequency of Pathogenic Germline Variants Among Prostate Cancer Patients Utilizing Multi-Gene Panel Genetic Testing

Background

Germline genetic testing (GGT) has significant implications in the management of patients with prostate cancer (PCa). Herein, we report on patterns and frequency of pathogenic/likely pathogenic germline variants (P/LPGVs) among newly diagnosed Arab patients with PCa.

Methods

Patients meeting the National Comprehensive Cancer Network (NCCN) eligibility criteria for GGT were offered a 19-gene PCa panel or an expanded 84-gene multi-cancer panel.

Results

During the study period, 231 patients were enrolled; 107 (46.3%) had metastatic disease at diagnosis. In total, 17 P/LPGVs were detected in 17 patients (7.4%). Among the 113 (48.9%) patients who underwent GGT with the 19-gene panel, eight (7.1%) had P/LPGVs, compared to nine (7.6%) of the 118 (51.1%) who did GGT through the expanded 84-gene panel (P = 0.88). Variant of uncertain significance (VUS) rate was higher (n = 73, 61.9%) among the group who underwent expanded 84-gene panel testing compared to those who underwent the 19-gene PCa panel (n = 35, 30.9%) (P = 0.001). P/LPGVs in DNA damage repair (DDR) genes, most frequently BRCA2, CHEK2 and TP53, were the most common P/LPGVs findings.

Conclusion

This study is the first to characterize the germline genetic profile of an Arab population with PCa. All detected P/LPGVs were potentially actionable, with most variants able to be detected with a PCa-specific panel.

Extremely Low Birth Weight Infant (Gestational Age of 29 Weeks) With Kabuki Syndrome Type I: Case Report and Literature Review

BACKGROUND

This paper aimed to investigate the clinical phenotype of Kabuki syndrome (KS) in premature infants.

METHODS

This paper presents a case of an extremely low birth weight infant (gestational age 29 weeks) with KS1 caused by a variant in the KMT2D gene. The clinical, pathological, and differential diagnostic findings were comprehensively analyzed. A thorough literature review was also performed to enhance the understanding of KS, revealing its unique features and prognostic significance.

RESULTS

The infant was a male with a gestational age of 29 weeks and a birth weight of 850 g. He had intrauterine growth retardation, characterized by cleft palate, sacrococcygeal skin depressions, and recurrent metabolic acidosis. Whole-exome sequencing revealed the c.4267C > T (p.Arg1423Cys) variant in the KMT2D gene, which was absent in his parents. The patient was discharged after 67 days of treatment, and he was followed up to 19 months of corrected gestational age, with growth retardation and expression language delay. Ten previous studies on preterm infants were retrieved, with 10 preterm infants. They all had characteristic facial features, such as long blepharophimosis, sparse and lateral 1/3 eyebrows, and large and prominent/cupped ears. Other manifestations were extrauterine growth delay (7/10), abnormal development of the cardiovascular system (7/10), abnormal development of the nervous system (5/10), and cleft palate (2/10).

CONCLUSIONS

Kabuki syndrome is a rare hereditary disorder involving multiple organs and systems. Genetic assessment for preterm infants with congenital abnormalities is recommended.

Inorganic pyrophosphate plasma levels in patients with GGCX-associated PXE-like phenotypes

Introduction

Pseudoxanthoma elasticum (PXE) is an autosomal recessive ectopic calcification disorder clinically affecting the skin, eyes, and vascular system. Most cases of PXE are caused by inactivating pathogenic variants in the ABCC6 gene encoding a hepatic transmembrane efflux transporter, which facilitates the extracellular release of ATP, the precursor of inorganic pyrophosphate (PPi), a potent endogenous inhibitor of calcification. Pathogenic variants in GGCX, encoding γ-glutamyl carboxylase required for activation of vitamin K-dependent coagulation factors as well as matrix Gla protein (MGP) and Gla-rich protein (GRP), two inhibitors of ectopic calcification, have also been reported to cause cutaneous changes like those seen in PXE. While ectopic calcification in ABCC6 deficiency has been associated with reduced plasma levels of PPi due to loss of ABCC6 transport activity in the liver, plasma PPi levels have not been reported in patients with GGCX-associated phenotypes.

Methods

We analyzed five patients from three unrelated families on their clinical, laboratory, and molecular findings who carry biallelic variants in GGCX and present with phenotypic characteristics associated with PXE. The variants were identified using a next-generation sequencing panel consisting of 29 genes associated with ectopic calcification.

Results and conclusion

This study demonstrates that in addition to ABCC6, GGCX variants can cause the PXE phenotype, expanding PXE and perhaps other heritable ectopic calcification disorders' clinical and genetic heterogeneity. The results also show that the plasma concentrations of PPi in these patients are not reduced compared to healthy control individuals, suggesting that plasma PPi does not govern ectopic calcification in GGCX deficiency.

Prevalence and Reclassification of Genetic Variants in South African Populations with Breast Cancer

Concurrent testing of numerous genes for hereditary breast cancer (BC) is available but can result in management difficulties. We evaluated use of an expanded BC gene panel in women of diverse South African ancestries and assessed use of African genomic data to reclassify variants of uncertain significance (VUS). A total of 331 women of White, Black African, or Mixed Ancestry with BC had a 9-gene panel test, with an additional 75 genes tested in those without a pathogenic/likely pathogenic (P/LP) variant. The proportion of VUS reclassified using ClinGen gene-specific allele frequency (AF) thresholds or an AF > 0.001 in nonguidelines genes in African genomic data was determined. The 9-gene panel identified 58 P/LP variants, but only two of the P/LP variants detected using the 75-gene panel were in confirmed BC genes, resulting in a total of 60 (18.1%) in all participants. P/LP variant prevalence was similar across ancestry groups, but VUS prevalence was higher in Black African and Mixed Ancestry than in White participants. In total, 611 VUS were detected, representing 324 distinct variants. 10.8% (9/83) of VUS met ClinGen AF thresholds in genomic data while 10.8% (26/240) in nonguideline genes had an AF > 0.001. Overall, 27.0% of VUS occurrences could potentially be reclassified using African genomic data. Thus, expanding the gene panel yielded few clinically actionable variants but many VUS, particularly in participants of Black African and Mixed Ancestry. However, use of African genomic data has the potential to reclassify a significant proportion of VUS.

Clinical utility of comprehensive gene panel testing for common and rare causes of skeletal dysplasia and other skeletal disorders: Results from the largest cohort to date

Molecular genetics enables more precise diagnoses of skeletal dysplasia and other skeletal disorders (SDs). We investigated the clinical utility of multigene panel testing for 5011 unrelated individuals with SD in the United States (December 2019-April 2022). Median (range) age was 8 (0-90) years, 70.5% had short stature and/or disproportionate growth, 27.4% had a positive molecular diagnosis (MDx), and 30 individuals received two MDx. Genes most commonly contributing to MDx were FGFR3 (16.9%), ALPL (13.0%), and COL1A1 (10.3%). Most of the 112 genes associated with ≥1 MDx were primarily involved in signal transduction (n = 35), metabolism (n = 23), or extracellular matrix organization (n = 17). There were implications associated with specific care/treatment options for 84.4% (1158/1372) of MDx-positive individuals; >50% were linked to conditions with targeted therapy approved or in clinical development, including osteogenesis imperfecta, achondroplasia, hypophosphatasia, and mucopolysaccharidosis. Forty individuals with initially inconclusive results became MDx-positive following family testing. Follow-up mucopolysaccharidosis enzyme activity testing was positive in 14 individuals (10 of these were not MDx-positive). Our findings showed that inclusion of metabolic genes associated with SD increased the clinical utility of a gene panel and confirmed that integrated use of comprehensive gene panel testing with orthogonal testing reduced the burden of inconclusive results.

DIAGNOSTIC YIELD OF AN INHERITED RETINAL DISEASE GENE PANEL IN RETINOPATHY OF UNKNOWN ORIGIN

PURPOSE

Evaluating the presence of class 3, 4, and 5 genetic variants in inherited retinal disease (IRD) genes in patients with retinopathy of unknown origin (RUO).

METHODS

Multicentric retrospective study of RUO cases diagnosed between January 2012 and February 2022. General and ophthalmologic history, complete ophthalmologic examination, antiretinal antibodies, and IRD gene panel results were analyzed in every patient. Four RUO categories were defined: nonparaneoplastic autoimmune retinopathy, unilateral pigmentary retinopathy, asymmetrical pigmentary retinopathy, and acute zonal occult outer retinopathy.

RESULTS

The authors included 12 patients (9 females) across these four RUO categories. Mean age at inclusion was 45.6 years (20-68 years). Seven patients demonstrated class 3 variants in IRD genes. Of these, two also demonstrated class 5 variants in other IRD genes. The remaining five patients had negative panel results. IRD gene panel analysis allowed diagnosis refinement in 1 (8.3%) nonparaneoplastic autoimmune retinopathy patient in the RUO cohort. When considering the nonparaneoplastic autoimmune retinopathy subpopulation only, a higher diagnostic yield of 20% (1/5 patients) was achieved.

CONCLUSION

Every suspected nonparaneoplastic autoimmune retinopathy patient should benefit from gene panel testing to not overlook undiagnosed IRDs. By contrast, unilateral pigmentary retinopathy, asymmetrical pigmentary retinopathy, and acute zonal occult outer retinopathy subpopulations did not benefit from genetic testing in this study.

Diagnostic and clinical utility of comprehensive multigene panel testing for patients with neuropathy

BACKGROUND AND AIMS

Prior to next-generation sequencing (NGS), the evaluation of a patient with neuropathy typically consisted of screening for acquired causes, followed by clinical genetic testing of PMP22, MFN2, GJB1, and MPZ in patients with a positive family history and symptom onset prior to age 50. In this study, we examined the clinical utility of NGS in a large cohort of patients analyzed in a commercial laboratory.

METHODS

A cohort of 6849 adult patients underwent clinician-ordered peripheral neuropathy multigene panel testing ranging from 66 to 111 genes that included NGS and intragenic deletion/duplication analysis.

RESULTS

A molecular diagnosis was identified for 8.4% of the cohort (n = 573/6849). Variants in PMP22, MFN2, GJB1, MPZ, and TTR accounted for 73.8% of molecular diagnoses. Results had potential clinical actionability for 398 (69.5%) patients. Our results suggest that 225/573 (39.3%) of molecular diagnoses and 113/398 (28.4%) of clinical interventions would have been missed if the testing approach had been restricted to older guidelines.

INTERPRETATION

Our results highlight the need for expanded genetic testing guidelines that account for the increased number of genes associated with hereditary neuropathy, address the overlap of acquired and hereditary neuropathy, and provide broader access to genetic diagnosis for patients.

Expanding the genetic landscape of Usher syndrome type IV caused by pathogenic ARSG variants

Usher syndrome (USH) is the most common cause of deafblindness. USH is autosomal recessively inherited and characterized by rod-cone dystrophy or retinitis pigmentosa (RP), often accompanied by sensorineural hearing loss. Variants in >15 genes have been identified as causative for clinically and genetically distinct subtypes. Among the ultra-rare and recently discovered genes is ARSG, coding for the lysosomal sulfatase Arylsulfatase G. This subtype was assigned as "USH IV" with a late onset of RP and usually late-onset progressive SNHL without vestibular involvement. Here, we describe nine new subjects and the clinical description of four cases with the USH IV phenotype bearing seven novel and two known pathogenic variants. Functional experiments indicated the complete loss of sulfatase enzymatic activity upon ectopic expression of mutated ARSG cDNA. Interestingly, we identified a homozygous missense variant, p.(Arg99His), previously described in dogs with neuronal ceroid lipofuscinosis. Our study expands the genetic landscape of ARSG-USH IV and the number of known subjects by more than 30%. These findings highlight that USH IV likely has been underdiagnosed and emphasize the need to test molecularly unresolved subjects with deafblindness syndrome. Finally, testing of ARSG should be considered for the genetic work-up of apparent isolated inherited retinal diseases.

Germline multigene panel testing in acute and chronic pancreatitis

BACKGROUND/OBJECTIVES

Germline genetic testing is recommended for younger patients with idiopathic pancreatitis but there has been a lack of consensus in recommendations for those over age 35. We aimed to analyze the results of genetic testing among subjects of varying ages.

METHODS

Individuals who underwent germline multigene testing for pancreatitis susceptibility genes (CASR, CFTR, CPA1, CTRC, PRSS1, SPINK1) through a large commercial laboratory between 2017 and 2022 were included. Test results and information collected from test requisition forms were evaluated. Multivariable logistic regression models were performed to identify factors associated with a positive pancreatitis panel (pathogenic, likely pathogenic, and/or increased risk variants) in pancreatitis-related genes.

RESULTS

Overall, 2,468 subjects with primary indication of acute pancreatitis (AP) (n = 401), chronic pancreatitis (CP) (n = 631), pancreatic cancer (n = 128), or other indications (n = 1,308) completed germline testing. Among patients with AP or CP, the prevalence of any positive result for those <35 versus ≥35 years of age was 32.1% and 24.5% (p = 0.007), and the prevalence of a clinically meaningful result was 10.8% and 5.4%, respectively (p = 0.001). Positive family history of pancreatitis was associated with increased odds ratio (OR) of 8.59 (95% confidence interval (CI) 2.92-25.25) for a clinically significant panel result while each 5-year increase in age at test completion had lower odds (OR 0.89, 95% CI 0.83-0.95).

CONCLUSIONS

The highest prevalence of pathogenic variants is seen in younger individuals with a positive family history of pancreatitis. However, clinically meaningful results are identified in older subjects, suggesting that genetic counseling and testing should be considered for all age groups.

Cardiac conduction disorders in young adults: Clinical characteristics and genetic background of an underestimated population

BACKGROUND

Cardiac conduction disorder (CCD) in patients <50 years old is a rare and mostly unknown condition.

OBJECTIVE

We aimed to assess clinical characteristics and genetic background of patients <50 years old with CCD of unknown origin.

METHODS

We retrospectively reviewed a consecutive series of patients with a diagnosis of CCD before the age of 50 years referred to our center between January 2019 and December 2021. Patients underwent complete clinical examination and genetic evaluation.

RESULTS

We enrolled 39 patients with a median age of 40 years (28-47 years) at the onset of symptoms. A cardiac implantable electronic device was implanted in 69% of the patients. In 15 of 39 CCD index patients (38%), we found a total of 13 different gene variations (3 pathogenic, 6 likely pathogenic, and 4 variants of uncertain significance), mostly in 3 genes (SCN5A, TRPM4, and LMNA). In our cohort, genetic testing led to the decision to implant an implantable cardioverter-defibrillator in 2 patients for the increased risk of sudden cardiac death.

CONCLUSION

Patients with the occurrence of CCD before the age of 50 years present with a high rate of pathologic gene variations, mostly in 3 genes (SCN5A, TRPM4, and LMNA). The presence of pathogenic variations may add information about the prognosis and lead to an individualized therapeutic approach.

ALS Identified: two-year findings from a sponsored ALS genetic testing program

OBJECTIVE

To report initial results from the Amyotrophic Lateral Sclerosis (ALS) Identified genetic testing (GT) program on characteristics of individuals tested and frequency of reported disease-causing variants.

METHODS

ALS Identified used the Invitae Amyotrophic Lateral Sclerosis panel (Invitae, San Francisco, CA, USA) to assay 22 ALS-associated genes. Sponsored by Biogen (Cambridge, MA, USA), the program was launched in June 2021 and was available at no charge to individuals ≥18 years in the United States and Puerto Rico with an ALS diagnosis or a known family history of ALS. Deidentified data were available to Biogen.

RESULTS

As of 26 October 2023, 998 healthcare professionals ordered the panel at 681 unique care sites. Of 8054 individuals examined, 7483 (92.9%) were reported to have a clinical diagnosis of ALS, while 571 (7.1%) were asymptomatic relatives. Of the individuals with a clinical ALS diagnosis, 57.7% were male (n = 4319) and 42.3% female (n = 3164). Mean (SD) age at diagnosis is 62 (13) years. Out of the 7483 clinically diagnosed individuals, 1810 (24.2%) showed genetic variations in ALS-associated genes. Among these, 865 individuals (47.8%) carried pathogenic variants, and 44 (2.4%) had likely pathogenic variants, totaling 12.1% of the clinically diagnosed population.

INTERPRETATION

Since 2021 there has been robust uptake and sustained use of the ALS Identified program, one of the largest samples of people with ALS to date across the United States, demonstrating the interest and need for genetic ALS testing.