Developmental epileptic encephalopathy in DLG4-related synaptopathy

OBJECTIVE

The postsynaptic density protein of excitatory neurons PSD-95 is encoded by discs large MAGUK scaffold protein 4 (DLG4), de novo pathogenic variants of which lead to DLG4-related synaptopathy. The major clinical features are developmental delay, intellectual disability (ID), hypotonia, sleep disturbances, movement disorders, and epilepsy. Even though epilepsy is present in 50% of the individuals, it has not been investigated in detail. We describe here the phenotypic spectrum of epilepsy and associated comorbidities in patients with DLG4-related synaptopathy.

METHODS

We included 35 individuals with a DLG4 variant and epilepsy as part of a multicenter study. The DLG4 variants were detected by the referring laboratories. The degree of ID, hypotonia, developmental delay, and motor disturbances were evaluated by the referring clinician. Data on awake and sleep electroencephalography (EEG) and/or video-polygraphy and brain magnetic resonance imaging were collected. Antiseizure medication response was retrospectively assessed by the referring clinician.

RESULTS

A large variety of seizure types was reported, although focal seizures were the most common. Encephalopathy related to status epilepticus during slow-wave sleep (ESES)/developmental epileptic encephalopathy with spike-wave activation during sleep (DEE-SWAS) was diagnosed in >25% of the individuals. All but one individual presented with neurodevelopmental delay. Regression in verbal and/or motor domains was observed in all individuals who suffered from ESES/DEE-SWAS, as well as some who did not. We could not identify a clear genotype-phenotype relationship even between individuals with the same DLG4 variants.

SIGNIFICANCE

Our study shows that a subgroup of individuals with DLG4-related synaptopathy have DEE, and approximately one fourth of them have ESES/DEE-SWAS. Our study confirms DEE as part of the DLG4-related phenotypic spectrum. Occurrence of ESES/DEE-SWAS in DLG4-related synaptopathy requires proper investigation with sleep EEG.

Unraveling a history of overlap: A phenotypic comparison of RBCK1-related disease and glycogen storage disease type IV

RBCK1-related disease is a rare, multisystemic disorder for which our current understanding of the natural history is limited. A number of individuals initially carried clinical diagnoses of glycogen storage disease IV (GSD IV), but were later found to harbor RBCK1 pathogenic variants, demonstrating challenges of correctly diagnosing RBCK1-related disease. This study carried out a phenotypic comparison between RBCK1-related disease and GSD IV to identify features that clinically differentiate these diagnoses. Literature review and retrospective chart review identified 25 individuals with RBCK1-related disease and 36 with the neuromuscular subtype of GSD IV. Clinical features were evaluated to assess for statistically significant differences between the conditions. At a system level, any cardiac, autoinflammation, immunodeficiency, growth, or dermatologic involvement were suggestive of RBCK1, whereas any respiratory involvement suggested GSD IV. Several features warrant further exploration as predictors of RBCK1, such as generalized weakness, heart transplant, and recurrent infections, among others. Distinguishing RBCK1-related disease will facilitate correct diagnoses and pave the way for accurately identifying affected individuals, as well as for developing management recommendations, treatment, and an enhanced understanding of the natural history. This knowledge may also inform which individuals thought to have GSD IV should undergo reevaluation for RBCK1.

Consensus recommendations for the treatment and management of patients with Fabry disease on migalastat: a modified Delphi study

Objective

Fabry disease is a progressive disorder caused by deficiency of the α-galactosidase A enzyme (α-Gal A), leading to multisystemic organ damage with heterogenous clinical presentation. The addition of the oral chaperone therapy migalastat to the available treatment options for Fabry disease is not yet universally reflected in all treatment guidelines. These consensus recommendations are intended to provide guidance for the treatment and monitoring of patients with Fabry disease receiving migalastat.

Methods

A modified Delphi process was conducted to determine consensus on treatment decisions and monitoring of patients with Fabry disease receiving migalastat. The multidisciplinary panel comprised 14 expert physicians across nine specialties and two patients with Fabry disease. Two rounds of Delphi surveys were completed and recommendations on the use of biomarkers, multidisciplinary monitoring, and treatment decisions were generated based on statements that reached consensus.

Results

The expert panel reached consensus agreement on 49 of 54 statements, including 16 that reached consensus in round 1. Statements that reached consensus agreement are summarized in recommendations for migalastat treatment and monitoring, including baseline and follow-up assessments and frequency. All patients with Fabry disease and an amenable mutation may initiate migalastat treatment if they have evidence of Fabry-related symptoms and/or organ involvement. Treatment decisions should include holistic assessment of the patient, considering clinical symptoms and organ involvement as well as patient-reported outcomes and patient preference. The reliability of α-Gal A and globotriaosylsphingosine as pharmacodynamic response biomarkers remains unclear.

Conclusion

These recommendations build on previously published guidelines to highlight the importance of holistic, multidisciplinary monitoring for patients with Fabry disease receiving migalastat, in addition to shared decision-making regarding treatments and monitoring throughout the patient journey. GRAPHICAL ABSTRACT.

A genotype-first approach identifies high incidence of NF1 pathogenic variants with distinct disease associations

Loss of function variants in the NF1 gene cause neurofibromatosis type 1 (NF1), a genetic disorder characterized by complete penetrance, prevalence of 1 in 3,000, characteristic physical exam findings, and a substantially increased risk for malignancy. However, our understanding of the disorder is entirely based on patients ascertained through phenotype-first approaches. Leveraging a genotype-first approach in two large patient cohorts, we demonstrate unexpectedly high prevalence (1 in 450-750) of NF1 pathogenic variants. Half were identified in individuals lacking clinical features of NF1, with many appearing to have post-zygotic mosaicism for the identified variant. Incidentally discovered variants were not associated with classic NF1 features but were associated with an increased incidence of malignancy compared to a control population. Our findings suggest that NF1 pathogenic variants are substantially more common than previously thought, often characterized by somatic mosaicism and reduced penetrance, and are important contributors to cancer risk in the general population.

Unmasking the challenges of Kabuki syndrome in adulthood: A case series

Kabuki syndrome is a recognizable Mendelian disorder characterized by the clinical constellation of childhood hypotonia, developmental delay or intellectual impairment, and characteristic dysmorphism resulting from monoallelic pathogenic variants in KMT2D or KDM6A. In the medical literature, most reported patients are children, and data is lacking on the natural history of the condition across the lifespan, with little known about adult-specific presentations and symptoms. Here, we report the results of a retrospective chart review of eight adult patients with Kabuki syndrome, seven of whom are molecularly confirmed. We use their trajectories to highlight the diagnostic challenges unique to an adult population, expand on neurodevelopmental/psychiatric phenotypes across the lifespan, and describe adult-onset medical complications, including a potential cancer risk and unusual and striking premature/accelerated aging phenotype.

An ACVR1R375P pathogenic variant in two families with mild fibrodysplasia ossificans progressiva

Genetic variants are vital in informing clinical phenotypes, aiding physical diagnosis, guiding genetic counseling, understanding the molecular basis of disease, and potentially stimulating drug development. Here we describe two families with an ultrarare ACVR1 gain-of-function pathogenic variant (codon 375, Arginine > Proline; ACVR1^R375P ) responsible for a mild nonclassic fibrodysplasia ossificans progressiva (FOP) phenotype. Both families include people with the ultrarare ACVR1^R375P variant who exhibit features of FOP while other individuals currently do not express any clinical signs of FOP. Thus, the mild ACVR1^R375P variant greatly expands the scope and understanding of this rare disorder.

Heterozygous variant in WNT1 gene in two brothers with early onset osteoporosis

Osteoporosis is a multifactorial disorder characterized by low bone mass and strength, leading to increased risk of fracture. The WNT pathway plays a critical role in bone remodeling by enhancing osteoblastic differentiation, which promotes bone formation, and inhibiting osteoclastic differentiation, decreasing bone resorption. Therefore, genetic alterations of this pathway will lead to impaired bone homeostasis and could contribute to varying response to treatment. We present the case of two brothers with early osteoporosis who were found to have a heterozygous variant of unknown significance in the WNT1 gene, c.1060_1061delCAinsG (p.H354Afs*39). This finding demonstrates that frameshift variants in WNT1 may also act in a dominant fashion leading to decreased bone mass.

Expanding the genotypic and phenotypic spectrum in a diverse cohort of 104 individuals with Wiedemann-Steiner syndrome

Wiedemann-Steiner syndrome (WSS) is an autosomal dominant disorder caused by monoallelic variants in KMT2A and characterized by intellectual disability and hypertrichosis. We performed a retrospective, multicenter, observational study of 104 individuals with WSS from five continents to characterize the clinical and molecular spectrum of WSS in diverse populations, to identify physical features that may be more prevalent in White versus Black Indigenous People of Color individuals, to delineate genotype-phenotype correlations, to define developmental milestones, to describe the syndrome through adulthood, and to examine clinicians' differential diagnoses. Sixty-nine of the 82 variants (84%) observed in the study were not previously reported in the literature. Common clinical features identified in the cohort included: developmental delay or intellectual disability (97%), constipation (63.8%), failure to thrive (67.7%), feeding difficulties (66.3%), hypertrichosis cubiti (57%), short stature (57.8%), and vertebral anomalies (46.9%). The median ages at walking and first words were 20 months and 18 months, respectively. Hypotonia was associated with loss of function (LoF) variants, and seizures were associated with non-LoF variants. This study identifies genotype-phenotype correlations as well as race-facial feature associations in an ethnically diverse cohort, and accurately defines developmental trajectories, medical comorbidities, and long-term outcomes in individuals with WSS.

What is new with 22q? An update from the 22q and You Center at the Children's Hospital of Philadelphia

22q11.2 deletion syndrome (22q11.2DS) is a disorder caused by recurrent, chromosome-specific, low copy repeat (LCR)-mediated copy-number losses of chromosome 22q11. The Children's Hospital of Philadelphia has been involved in the clinical care of individuals with what is now known as 22q11.2DS since our initial report of the association with DiGeorge syndrome in 1982. We reviewed the medical records on our continuously growing longitudinal cohort of 1,421 patients with molecularly confirmed 22q11.2DS from 1992 to 2018. Most individuals are Caucasian and older than 8 years. The mean age at diagnosis was 3.9 years. The majority of patients (85%) had typical LCR22A-LCR22D deletions, and only 7% of these typical deletions were inherited from a parent harboring the deletion constitutionally. However, 6% of individuals harbored other nested deletions that would not be identified by traditional 22q11.2 FISH, thus requiring an orthogonal technology to diagnose. Major medical problems included immune dysfunction or allergies (77%), palatal abnormalities (67%), congenital heart disease (64%), gastrointestinal difficulties (65%), endocrine dysfunction (>50%), scoliosis (50%), renal anomalies (16%), and airway abnormalities. Median full-scale intelligence quotient was 76, with no significant difference between individuals with and without congenital heart disease or hypocalcemia. Characteristic dysmorphic facial features were present in most individuals, but dermatoglyphic patterns of our cohort are similar to normal controls. This is the largest longitudinal study of patients with 22q11.2DS, helping to further describe the condition and aid in diagnosis and management. Further surveillance will likely elucidate additional clinically relevant findings as they age.

Mitral valve prolapse and aortic root dilation in adults with hypermobile Ehlers-Danlos syndrome and related disorders

Ehlers-Danlos syndromes (EDSs) are a group of inherited connective tissue disorders, and among them, classical EDS (cEDS) and hypermobile EDS (hEDS) are the most common. Mitral valve prolapse (MVP) and aortic root dilation (ARD) have previously been reported to occur at an increased frequency within cEDS and hEDS. More recently, a study performed in the pediatric population did not show increased prevalence (Ritter et al., American Journal of Medical Genetics Part A, 173(6), 1467-1472, 2017). The purpose of this study was to review a large population of individuals with cEDS, hEDS, and hypermobility spectrum disorders to determine the frequency of MVP and ARD. A retrospective chart review of 209 individuals with echocardiograms was performed. Overall, 6.4% (13/209) had MVP and 1.6% (3/189) were found to have ARD. Although the presence of MVP is higher than what has been reported in the general population, no patients had severe MVP or required surgical intervention. No patients in this cohort had an aortic root diameter requiring surgical repair. Based on the results of this study and previous studies, routine echocardiograms to assess for valvular diseases and ARD may not be necessary unless warranted by presence of symptoms or family history.

A disease severity scoring system for children with type 1 Gaucher disease

Almost half of patients with Gaucher disease are diagnosed by the age of 10 years, and approximately two thirds are diagnosed by the age of 20 years. Besides symptomatic children, some presymptomatic children are being diagnosed through community screening programs and because of affected siblings. In addition, it is anticipated that in the near future, newborn screening for lysosomal diseases such as Gaucher disease will be introduced in the USA, identifying additional pre/nonsymptomatic children. Currently, there is no severity scoring system for children. A validated disease severity scoring system in the pediatric Gaucher population will be essential for classifying disease severity in these children, monitoring their disease progression, making decisions about when to treat them, and monitoring disease improvement with therapy. A severity scoring system will also be helpful in comparing therapeutic options as new therapies are designed. Therefore, a Pediatric Gaucher Severity Scoring System (PGS3) was devised using expert opinion and validated in 26 patients with type 1 Gaucher disease. The PGS3 correlates well with disease severity in patients at diagnosis and over time.

CONCLUSION

A practical system that will help clinical management, based on signs and symptoms in children with type 1 Gaucher disease, is presented.

Measurement of tissue acyl-CoAs using flow-injection tandem mass spectrometry: acyl-CoA profiles in short-chain fatty acid oxidation defects

The primary accumulating metabolites in fatty acid oxidation defects are intramitochondrial acyl-CoAs. Typically, secondary metabolites such as acylcarnitines, acylglycines and dicarboxylic acids are measured to study these disorders. Methods have not been adapted for tissue acyl-CoA measurement in defects with primarily acyl-CoA accumulation. Our objective was to develop a method to measure fatty acyl-CoA species that are present in tissues of mice with fatty acid oxidation defects using flow-injection tandem mass spectrometry. Following the addition of internal standards of [(13)C(2)] acetyl-CoA, [(13)C(8)] octanoyl-CoA, and [C(17)] heptadecanoic CoA, acyl-CoA's are extracted from tissue samples and are injected directly into the mass spectrometer. Data is acquired using a 506.9 neutral loss scan and multiple reaction-monitoring (MRM). This method can identify all long, medium and short-chain acyl-CoA species in wild type mouse liver including predicted 3-hydroxyacyl-CoA species. We validated the method using liver of the short-chain-acyl-CoA dehydrogenase (SCAD) knock-out mice. As expected, there is a significant increase in [C(4)] butyryl-CoA species in the SCAD -/- mouse liver compared to wild type. We then tested the assay in liver from the short-chain 3-hydroxyacyl-CoA dehydrogenase (SCHAD) deficient mice to determine the profile of acyl-CoA accumulation in this less predictable model. There was more modest accumulation of medium chain species including 3-hydroxyacyl-CoA's consistent with the known chain-length specificity of the SCHAD enzyme.

Ablepharon-Macrostomia syndrome--extension of the phenotype

Ablepharon-Macrostomia syndrome (AMS) is a rare collection of findings characterized by absent or hypoplastic eyelids, fusion defects of the mouth with unfused lateral commissures, abnormal ears, ambiguous genitalia, skin differences including dry and coarse skin or redundant folds of skin, and developmental delay. Fewer than 20 patients have been reported to date. These include a parent and two children and a recent report of a father and daughter, therefore suggesting autosomal dominant inheritance. Here we present one additional sporadic case with an expanded phenotype. This patient has more significant hand and foot anomalies than previously reported.