GLIMMERS: glioma molecular markers exploration using long-read sequencing

Summary

The revised WHO guidelines for classifying and grading brain tumors include several copy number variation (CNV) markers. The turnaround time for detecting CNVs and alterations throughout the entire genome is drastically reduced with the customized read incremental approach on the nanopore platform. However, this approach is challenging for non-bioinformaticians due to the need to use multiple software tools, extract CNV markers and interpret results, which creates barriers due to the time and specialized resources that are necessary. To address this problem and help clinicians classify and grade brain tumors, we developed GLIMMERS: glioma molecular markers exploration using long-read sequencing, an open-access tool that automatically analyzes nanopore-based CNV data and generates simplified reports.

Availability and implementation

GLIMMERS is available at https://gitlab.com/silol_public/glimmers under the terms of the MIT license.

Efficacy of Bortezomib for Treating Anti-Interferon-Gamma Autoantibody-Associated Adult-Onset Immunodeficiency Syndrome

BACKGROUND

Currently, there is no effective treatment for adult-onset immunodeficiency (AOID) syndrome with anti-interferon-gamma autoantibodies (anti-IFN-γ-auto-Abs). This study aimed to investigate the effectiveness of bortezomib (BTZ) for decreasing anti-IFN-γ-auto-Abs.

METHODS

A pre- and post-intervention study was conducted from February 2017 through June 2019 at Siriraj Hospital (Bangkok, Thailand). Five patients were invited to receive once-weekly BTZ (1.3 mg/m2 body surface area) subcutaneously for 8 weeks followed by oral cyclophosphamide (1 mg/kg/d) for 4 months. The primary outcomes were the difference in antibody level at 8 and 48 weeks compared with baseline and the incidence of serious adverse events (AEs). The secondary outcome was the occurrence of opportunistic infections (OIs) during the 72 weeks after starting BTZ.

RESULTS

The median patient age was 46 years (range, 34-53). All patients had 3-5 OIs prior to enrollment. All patients were receiving antimycobacterial agents for treatment of nontuberculous mycobacterial infection at enrollment. There was no significant difference in the mean optical density of auto-Abs at 8 weeks (3.73 ± 0.72) or 48 weeks (3.74 ± 0.53) compared with baseline (3.84 ± 0.49; P = .336 and P = .555, respectively). However, after serum dilution, the antibody titer nonsignificantly decreased 8-16 weeks after BTZ initiation (P = .345). Ten OIs were observed 24-72 weeks after BTZ initiation.

CONCLUSIONS

Treatment with BTZ followed by cyclophosphamide yielded no significant decrease in antibody titer levels, and 10 OIs were observed during 24-72 weeks of BTZ treatment. No serious AEs were observed. Combining rituximab with BTZ is likely necessary to prevent generation of new autoantibody-producing plasma cells. Clinical Trials Registration. NCT03103555.

Germline mutations of 4567 patients with hereditary breast-ovarian cancer spectrum in Thailand

Multi-gene panel testing has led to the detection of pathogenic/likely pathogenic (P/LP) variants in many cancer susceptibility genes in patients with breast-ovarian cancer spectrum. However, the clinical and genomic data of Asian populations, including Thai cancer patients, was underrepresented, and the clinical significance of multi-gene panel testing in Thailand remains undetermined. In this study, we collected the clinical and genetic data from 4567 Thai patients with cancer in the hereditary breast-ovarian cancer (HBOC) spectrum who underwent multi-gene panel testing. Six hundred and ten individuals (13.4%) had germline P/LP variants. Detection rates of germline P/LP variants in breast, ovarian, pancreatic, and prostate cancer were 11.8%, 19.8%, 14.0%, and 7.1%, respectively. Non-BRCA gene mutations accounted for 35% of patients with germline P/LP variants. ATM was the most common non-BRCA gene mutation. Four hundred and thirty-two breast cancer patients with germline P/LP variants (80.4%) met the current NCCN genetic testing criteria. The most common indication was early-onset breast cancer. Ten patients harbored double pathogenic variants in this cohort. Our result showed that a significant proportion of non-BRCA P/LP variants were identified in patients with HBOC-related cancers. These findings support the benefit of multi-gene panel testing for inherited cancer susceptibility among Thai HBOC patients. Some modifications of the testing policy may be appropriate for implementation in diverse populations.

A cost-utility analysis of BRCA1 and BRCA2 testing in high-risk breast cancer patients and family members in Thailand: a cost-effective policy in resource-limited settings

Background

Screening for germline pathogenic BRCA1 or BRCA2 variants (gBRCA) in high-risk breast cancer patients is known to be cost-effective in high-income countries. Nationwide adoption of genetics testing in high-risk breast cancer population remains poor. Our study aimed to assess gBRCA health economics data in the middle-income country setting of Thailand.

Methods

Decision tree and Markov model were utilized to assess cost-utility between the testing vs. no-testing groups from a societal and lifetime perspective and lifetime. We interviewed 264 patients with breast/ovarian cancer and their family members to assess relevant costs and quality of life using EQ-5D-5L. One-way sensitivity, probabilistic sensitivity (Monte Carlo simulation), and budget impact analyses were done to estimate the outcome under Thailand's Universal Health Coverage scheme.

Results

The predicted lifetime cost and Quality-adjusted Life Years (QALY) for those with breast cancer were $13,788 and 10.22 in the testing group and $13,702 and 10.07 in the no-testing group. The incremental cost-effectiveness ratio for gBRCA testing in high-risk breast cancer patients was $573/QALY. The lifetime cost for the family members of those with gBRCA was $14,035 (QALY 9.99), while the no-testing family members group was $14,077 (QALY 9.98). Performing gBRCA testing in family members was cost-saving.

Conclusion

Cost-utility analysis demonstrated a cost-effective result of gBRCA testing in high-risk breast cancer patients and cost-saving in familial cascade testing. The result was endorsed in the national health benefits package in 2022. Other middle-income countries may observe the cost-effective/cost-saving aspects in common genetic diseases under their national health schemes.

Exploring extracellular matrix and prostaglandin pathway alterations across varying resection margin distances of right-sided colonic adenocarcinoma

BACKGROUND

Surgical resection followed by indicated adjuvant therapy offers potential curative treatment in colonic adenocarcinoma. Beyond the well-established seed and soil theory of colon cancer progression, the 'normal-appearing' tissues near the tumor are not genuinely normal and remain as remnants in patients following surgery. Our objective was to elucidate the alteration of gene expression and pathways across various distances of resection margins in right-sided colonic adenocarcinoma.

METHODS

Twenty-seven fresh samples of primary cancer and 56 matched non-tumor tissues adjacent to the tumor (NAT) were collected from patients with resectable right-sided colon cancer. NAT were systematically obtained at varying distances (1, 5, and 10 cm) on both proximal and distal sides. Comprehensive gene expression analysis was performed using 770-gene PanCancer Progression Panel, delineating distinctive pathways and functional predictions for each region.

RESULTS

Distinctive gene signatures and pathways exhibited by normal-appearing tissues were discovered at varying distances from cancer. Notably, SFRP2, PTGDS, COL1A1, IL1B, THBS2, PTGIS, COL1A2, NPR1, and BGN were upregulated, while ENPEP, MMP1, and NRCAM were downregulated significantly in 1-cm tissue compared to farther distances. Substantial alterations in the extracellular matrix (ECM) and prostaglandin/thromboxane synthesis were significantly evident at the 1-cm distance. Functional analysis indicated enhanced cell viability and survival, alongside reduced cellular death and apoptosis.

CONCLUSIONS

Different distances exerted a significant impact on gene alteration within the normal-looking mucosa surrounding primary cancer, influenced by various mechanisms. These findings may highlight potential therapeutic targets related to the ECM and prostaglandin/thromboxane pathways for treatment strategies.

Whole exome sequencing and rare variant association study to identify genetic modifiers, KLF1 mutations, and a novel double mutation in Thai patients with hemoglobin E/beta-thalassemia

OBJECTIVES

Clinical manifestations of patients with Hemoglobin E/beta-thalassemia vary from mild to severe phenotypes despite exhibiting the same genotype. Studies have partially identified genetic modifiers. We aimed to study the association between rare variants in protein-coding regions and clinical severity in Thai patients.

METHODS

From April to November 2018, a case-control study was conducted based on clinical information and DNA samples collected from Thai patients with hemoglobin E/beta-thalassemia over the age of four years. Cases were patients with severe symptoms, while patients with mild symptoms acted as controls. Whole exome sequencing and rare variant association study were used to analyze the data.

RESULTS

All 338 unrelated patients were classified into 165 severe and 173 mild cases. Genotypes comprised 81.4% of hemoglobin E/beta-thalassemia, 2.7% of homozygous or compound heterozygous beta-thalassemia, and 0.3% of (δβ)⁰ thalassemia Hb E while 15.7% of samples were not classified as beta-thalassemia. A novel cis heterozygotes of IVS I-7 (A > T) and codon 26 (G > A) was identified. Six genes (COL4A3, DLK1, FAM186A, PZP, THPO, and TRIM51) showed the strongest associations with severity (observed p-values of <0.05; significance lost after correction for multiplicity). Among known modifiers, KLF1 variants were found in four mild patients and one severe patient.

CONCLUSION

No rare variants were identified as contributors to the clinical heterogeneity of hemoglobin E/beta-thalassemia. KLF1 mutations are potential genetic modifiers. Studies to identify genetic factors are still important and helpful for predicting severity and developing targeted therapy.

Ultrarapid and high-resolution HLA class I typing using transposase-based nanopore sequencing applied in pharmacogenetic testing

Nanopore sequencing has been examined as a method for rapid and high-resolution human leukocyte antigen (HLA) typing in recent years. We aimed to apply ultrarapid nanopore-based HLA typing for HLA class I alleles associated with drug hypersensitivity, including HLA-A*31:01, HLA-B*15:02, and HLA-C*08:01. Most studies have used the Oxford Nanopore Ligation Sequencing kit for HLA typing, which requires several enzymatic reactions and remains relatively expensive, even when the samples are multiplexed. Here, we used the Oxford Nanopore Rapid Barcoding kit, which is transposase-based, with library preparation taking less than 1 h of hands-on time and requiring minimal reagents. Twenty DNA samples were genotyped for HLA-A, -B, and -C; 11 samples were from individuals of different ethnicity and nine were from Thai individuals. Two primer sets, a commercial set and a published set, were used to amplify the HLA-A, -B, and -C genes. HLA-typing tools that used different algorithms were applied and compared. We found that without using several third-party reagents, the transposase-based method reduced the hands-on time from approximately 9 h to 4 h, making this a viable approach for obtaining same-day results from 2 to 24 samples. However, an imbalance in the PCR amplification of different haplotypes could affect the accuracy of typing results. This work demonstrates the ability of transposase-based sequencing to report 3-field HLA alleles and its potential for race- and population-independent testing at considerably decreased time and cost.

Identification of Genomic Alterations in Thai Patients With Colorectal Cancer Using Next-Generation Sequencing-Based Multigene Cancer Panel

Introduction Colorectal cancer (CRC) is one of the leading causes of death and illness in the general population. Although the incidence of CRC is steadily decreasing worldwide, it is being diagnosed more in individuals under 50 years of age. Multiple disease-causing variants have been reported to be involved in the development of CRC. This study aimed to investigate the molecular and clinical characteristics of Thai patients with CRC. Methods NGS-based multigene cancer panel testing was performed on 21 unrelated patients. Target enrichment was performed using a custom-designed Ion AmpliSeq on-demand panel. Thirty-six genes associated with CRC and other cancer were analyzed for variant detection. Results Sixteen variants (five nonsense, eight missense, two deletions, and one duplication) in nine genes were identified in 12 patients. Eight (66.7%) patients harboring disease-causing deleterious variants in genes APC, ATM, BRCA2, MSH2, and MUTYH. One of the eight patients also carried additional heterozygous variants in genes ATM, BMPR1A, and MUTYH. In addition, four patients carried variants of uncertain significance in genes APC, MLH1, MSH2, STK11, and TP53. Among all detected genes, APC was the most frequent causative gene observed in CRC patients, which is consistent with previous reports. Conclusion This study demonstrated the comprehensive molecular and clinical characterization of CRC patients. These findings showed the benefits of using multigene cancer panel sequencing for pathogenic gene detection and showed the prevalence of genetic aberrations in Thai patients with CRC.

Abstract 2241: Transcriptomic analysis of tetraspanins in colorectal cancer

Introduction: Transmembrane proteins and their overexpression have been highly involved in malignancies. In particular, Tetraspanins (TSPANs)—a family of four-span transmembrane proteins—have been proposed as “master organizers” of multi-molecular membrane complexes by associating with specific partners and thus contributed to the progression of many cancer types. To date, transcriptomic analysis of all human TSPANs in colorectal cancer (CRC) has remained unclear. Here, we focused on utilizing next-generation RNA sequencing (RNA-Seq) to explore the expression level of TSPANs in primary tumor tissues of CRC, which is a complex disease and the second cause of cancer mortality worldwide.

Experimental Procedures: Resected primary tumor tissues of CRC were collected from 100 patients along with the written informed consents. Later, total RNA was extracted from all frozen patient tissues. RNA-Seq of those RNA samples was next done before the transcriptomic analysis of TSPANs in CRC was performed. Immunofluorescence (IF) and Immunohistochemistry (IHC) stains were also employed to confirm the target protein expression in formalin-fixed paraffin-embedded tissue (FFPE) slides from CRC patients.

Results: As a result of transcriptomic analysis of TSPANs in CRC tissues, among 33 human TSPANs, the high expression levels (transcript per million above the average of all TSPANs) of TSPAN1, TSPAN8, TSPAN24, TSPAN29 and TSPAN30 were observed in the patient-derived CRC tissues. Notably, the expression level of TSPAN8 was comparable with that of EPCAM, which is a well-known tumor marker. Moreover, the high expression of TSPAN8 protein could be clearly observed in both IF and IHC-stained FFPE slides from CRC patients. Our result highlights the possible relevance of these overexpressed TSPANs in CRC development.

Conclusions: This study is the first RNA-Seq-based transcriptomic analysis of all human TSPANs in CRC. Our finding suggests the significant overexpression of particular TSPANs, especially TSPAN8, in CRC. Further analyses will be beneficial for translational research in CRC. The overexpression of TSPANs may suggest a framework to further explore diagnostic, prognostic, and predictive surface biomarkers, therapeutic targets, and other applications for CRC.

Citation Format: Thanawat Suwatthanarak, Pariyada Tanjak, Amphun Chaiboonchoe, Onchira Acharayothin, Kullanist Thanormjit, Tharathorn Suwatthanarak, Watsaphon Tangkullayanone, Manop Pithukpakorn, Vitoon Chinswangwatanakul. Transcriptomic analysis of tetraspanins in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2241.

The KRAS-Mutant Consensus Molecular Subtype 3 Reveals an Immunosuppressive Tumor Microenvironment in Colorectal Cancer

Colorectal cancers (CRC) with KRAS mutations (KRAS^mut) are frequently included in consensus molecular subtype 3 (CMS3) with profound metabolic deregulation. We explored the transcriptomic impact of KRAS^mut, focusing on the tumor microenvironment (TME) and pathways beyond metabolic deregulation. The status of KRAS^mut in patients with CRC was investigated and overall survival (OS) was compared with wild-type KRAS (KRAS^wt). Next, we identified CMS, and further investigated differentially expressed genes (DEG) of KRAS^mut and distinctive pathways. Lastly, we used spatially resolved gene expression profiling to define the effect of KRAS^mut in the TME regions of CMS3-classified CRC tissues. CRC patients with KRAS^mut were mainly enriched in CMS3. Their specific enrichments of immune gene signatures in immunosuppressive TME were associated with worse OS. Activation of TGFβ signaling by KRAS^mut was related to reduced pro-inflammatory and cytokine gene signatures, leading to suppression of immune infiltration. Digital spatial profiling in TME regions of KRAS^mut CMS3-classified tissues suggested up-regulated genes, CD40, CTLA4, ARG1, STAT3, IDO, and CD274, that could be characteristic of immune suppression in TME. This study may help to depict the complex transcriptomic profile of KRAS^mut in immunosuppressive TME. Future studies and clinical trials in CRC patients with KRAS^mut should consider these transcriptional landscapes.

STK11 Causative Variants and Copy Number Variations Identified in Thai Patients With Peutz-Jeghers Syndrome

Introduction Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant inherited disorder caused by germline mutations in the serine-threonine kinase 11 (STK11) tumor suppressor gene. This syndrome is characterized by hamartomatous gastrointestinal polyps, mucocutaneous melanin pigmentation, and a higher risk of developing various cancers. Methods We summarized the clinical and molecular characteristics of five unrelated Thai patients with PJS. Denaturing high-performance liquid chromatography (DHPLC) screening, coupled with direct DNA sequencing and multiplex ligation-dependent probe amplification (MLPA), were applied for the molecular analysis of STK11. Results A total of four STK11 pathogenic changeswere identified in the five PJS patients, including two frameshift variants (a novel c.199dup, p.Leu67ProfsTer96 and a known c.834_835del, p.Cys278TrpfsTer6) and two types of copy number variations (CNV), exon 1 deletion and exons 2-3 deletion. Among reported STK11 exonic deletions, exon 1 and exons 2-3 deletions were found to be the two most commonly deleted exons. Conclusion All identified STK11 mutations were null mutations that were associated with more severe PJS phenotypes and cancers. This study broadens the phenotypic and mutational spectrum of STK11 in PJS.

Germline ATM mutation and somatic PIK3CA and BCOR mutations found in an infant with aggressive orbital embryonal rhabdomyosarcoma

Purpose

To report a case of aggressive infantile orbital embryonal rhabdomyosarcoma harboring germline ATM mutation and 2 somatic mutations as revealed by next-generation sequencing and the potential application for personalized therapy.

Observations

A 7-month-old male developed a rapidly progressive left proptosis over 6 weeks due to a large medial orbital mass. Biopsy revealed embryonal rhabdomyosarcoma. After the first cycle of chemotherapy, re-imaging showed interval tumor enlargement with intracranial extension. Craniotomy, combined with orbital exenteration, was performed. Tumor specimens and blood samples were sent for 596 gene DNA sequencing panels with RNA-sequencing focused on actionable mutations as well as gene fusion detection. Sequencing revealed 3 clinically relevant mutations: a germline ATM loss-of-function (LOF) mutation, a somatic PIK3CA gain-of-function mutation, and a somatic BCOR LOF mutation. No chromosomal translocation was detected. Workup for metastasis was positive for bone marrow involvement. Despite standard high-dose adjuvant chemotherapy in combination with radiation therapy, the patient died 10 months later with metastatic diseases.

Conclusions and importance

This case highlights an aggressive form of embryonal rhabdomyosarcoma in an infantile orbit. The presence of germline mutation may explain the increased chemo-resistance and adverse prognosis, and may be used as the target for genomic-directed therapy.

Identification of novel mutation in RANKL by whole-exome sequencing in a Thai family with osteopetrosis; a case report and review of RANKL osteopetrosis

Background

Osteopetrosis is a rare form of skeletal dysplasia characterized by increased bone density that leads to bone marrow failure, compressive neuropathy, and skeletal dysmorphism. Molecular diagnosis is essential as it guides treatment and prognosis. We report Thai siblings with an ultra‐rare form of osteopetrosis.

Methods

The older brother and the younger sister presented with chronic mandibular osteomyelitis in their 20s. Since childhood, they had visual impairment, pathological fracture, and skeletal dysmorphism.

Quadruplet whole‐exome sequencing was performed and confirmed with Sanger sequencing. Novel mutation in TNFSF11 (RANKL) c.842T>G, p.Phe281Cys was identified in a homozygous state in both siblings.

Results

Surgical debridement, antibiotic, and hyperbaric oxygen therapy were used and discontinued over a 6‐month period with normalization of C‐reactive protein. Hematopoietic stem cell transplantation candidacy was excluded by molecular diagnosis.

Conclusion

We report a novel mutation in an ultra‐rare form of osteopetrosis. Our siblings manifested with a milder phenotype in comparison with nine cases previously published.

Physician awareness, preparedness, and opinions toward consumer-initiated genetic testing in Thailand: Views from a changing landscape

Consumer-initiated genetic tests have captured public interest in recent years, including in low-to-middle-income countries (LMICs) such as Thailand. Due to limited resources and personnel, physicians will most likely bear the burden of increasing service needs from the public as consumer-initiated genetic tests become popularized. The primary objective of this study was to describe (a) awareness, (b) preparedness to provide counseling about the consumer-initiated genetic test, and (c) opinions on the usefulness of consumer-initiated genetic tests among physicians at an academic hospital in Bangkok, Thailand. The secondary objective was to describe factors that were associated with the awareness, preparedness, and opinion of the participants. Paper questionnaires were sent out to participants which included internal medicine residents, fellows, and faculty staff members. The questionnaires assessed awareness, preparedness to discuss consumer-initiated genetic test results, and opinion on the usefulness of consumer-initiated genetic tests and included both closed- and open-ended questions. Responses were anonymous. Among 308 participants, there were 223 (72.4%) residents, 14 (4.5%) fellows, and 71 (23.1%) staff members. Only 15% of participants were aware of consumer-initiated genetic tests, mostly from the internet, and only 7% were prepared to provide counseling regarding consumer-initiated genetic tests. However, 60% agreed that consumer-initiated genetic tests may be clinically useful. Many participants, including trainees, expressed concerns about the interpretation of consumer-initiated genetic test results, application into clinical practice, appropriate counseling, and patient referral to geneticists. Multivariate logistic regression revealed that years of work experience was independently associated with awareness of consumer-initiated genetic tests, while male gender and less work experience were independently associated with favorable opinion toward the usefulness of consumer-initiated genetic tests. Our results pointed to an urgent need for genetic counselors in Thailand. Also, physicians, particularly trainees, need appropriate training to prepare them for a rapidly evolving environment where consumer-initiated genetic tests become commonplace.

HLA-B*27:04 associated with enthesitis and younger age of onset, and HLA-B allele profile in patients with ankylosing spondylitis in Thailand: A cross-sectional study

AIM

The aims of this study were to estimate human leukocyte antigen (HLA)-B allele frequency, to identify alleles associated with ankylosing spondylitis (AS), and to explore manifestations in various HLA-B*27 in Thai AS patients.

METHODS

This was a cross-sectional study. Thai patients older than 18 years with diagnosed AS according to modified New York criteria who visited Siriraj Hospital (Bangkok, Thailand) were consecutively enrolled. HLA-B alleles were determined by reverse sequence-specific oligonucleotide assays, and were assigned at a 4-digit resolution. HLA-B alleles of 334 unrelated healthy Thai donors who participated in a previous phase 2b dengue vaccine clinical trial were included as controls. Odds ratio (OR) and Fisher's exact test were used to estimate association between allele and AS. The P value significance threshold was calculated according to Bonferroni.

RESULTS

Among the 88 patients who were recruited, 34 HLA-B alleles were identified, and all patients were heterozygous. The prevalence of HLA-B*27 was 89.8%, and 4 alleles of HLA-B*27 were identified. HLA-B*27:04 (OR: 39.4, P < .0001) and HLA-B*27:05 (OR: 13.8, P = .0011) were associated with AS. In contrast, HLA-B*27:06 was not found to be associated with AS (OR: 0.4, P = .241). AS patients carrying HLA-B*27:04 were more likely to have enthesitis and younger age at onset than those carrying HLA-B*27:05.

CONCLUSIONS

HLA-B*27:04 and HLA-B*27:05 were both found to be strongly associated with Thai AS. HLA-B*27:06 showed a neutral allele for Thai AS. AS patients with HLA-B*27:04 had more enthesitis and younger age at onset than those with HLA-B*27:05.

Successful treatment of arrhythmia with β-blocker and flecainide combination in pregnant patients with Andersen-Tawil syndrome: A case report and literature review

Andersen-Tawil syndrome (ATS) is a rare disorder characterized by a triad of ventricular arrhythmia (VA), dysmorphic features, and periodic paralysis. Due to the rarity of this condition, less is known about physiologic effect of pregnancy to ATS and arrhythmia. There is no established guideline for peripartum or postpartum treatment and prevention of arrhythmia in ATS; thus, the clinical management is challenging. We reported two KCNJ2-associated ATS patients who got pregnant and underwent vaginal birth safely. Both individuals had VA, micrognathia without periodic paralysis. β-blocker plus flecainide could be an effective treatment combination when monotherapy failed to control arrhythmia. VA of two pregnant patients with ATS could be controlled by either physiologic changes associated pregnancy or the combination treatment of β-blocker and flecainide.

High Frequency of KRAS Codon 146 and FBXW7 Mutations in Thai Patients with Stage II-III Colon Cancer

Background: KRAS, NRAS, and BRAF gene mutations are the most clinically relevant and frequently reported in colorectal cancer (CRC). Although data on these genes are frequently reported in several counties, data specific to these genes among Thai population are scarce. The aim of this study was to investigate and identify molecular alterations associated with colon cancer in Thai population, and to determine the impact of these genetic aberrations on clinical outcome. Methods: DNA from 108 archived formalin-fixed, paraffin-embedded (FFPE) tissue samples that histologically confirmed adenocarcinoma of stage II-III colon cancer between 2010 and 2012 at Siriraj Hospital (Bangkok, Thailand) were extracted. Gene mutational analysis was performed by next-generation sequencing (NGS) using an Oncomine Solid Tumor DNA kit (Thermo Fisher Scientific, Inc., Waltham, MA, USA). Results: A total of 22 somatic gene mutations were detected. The mutation frequency observed in KRAS, NRAS, BRAF, PIK3CA, and FBXW7 mutations was 47.2%, 1.9%, 1.9%, 12%, and 14.8%, respectively. KRAS mutation codon 12, 13, 59, 61, 117, and 146 mutations were identified in 29.6%, 8.3%, 1.8%, 0.9%, 0.0%, and 8.3%, respectively. KRAS Exon 4 had better DFS compared with Exon 2 and 3. Conclusions: This study is the first to comprehensively report hotspot mutations using NGS in Thai colon cancer patients. The most commonly identified gene mutation frequencies among Thai patients (KRAS, NRAS, BRAF, TP53, and PIK3CA) were similar to the gene mutation frequencies reported in Western population, except for subgroup of KRAS codon 146 and FBXW7 mutations that had a slightly higher frequency.

Clinical outcome and laboratory markers for predicting disease activity in patients with disseminated opportunistic infections associated with anti-interferon-γ autoantibodies

Background

Clinical courses and treatment outcomes are largely unknown in patients with adult-onset immunodeficiency associated with anti-interferon-gamma autoantibodies due to the fact that it was recently recognized and anti-IFN-γ auto-Abs detection is not widely available.

Methods and findings

Non-HIV-infected adult patients with detectable anti-IFN-γ auto-Abs diagnosed and followed at Siriraj Hospital, Bangkok, Thailand during January 2013 to November 2016 were prospectively studied. At each follow-up visit, patients were classified as stable or active disease according to symptoms and signs, and all proven OIs were recorded. Laboratory parameters, including erythrocyte sedimentation rate, C-reactive protein, and anti-IFN-γ auto-Abs level, were compared between active and stable disease episodes. We identified 80 patients with this clinical syndrome and followed them up during study period. Seventy-nine patients developed overall 194 proven opportunistic infections. Mycobacterium abscessus (34.5%) and Salmonella spp. (23.2%) were the two most common pathogens identified among these patients. Sixty-three patients were followed for a median of 2.7 years (range 0.6–4.8 years). Eleven (17.5%) patients achieved the drug-free remission period for at least 9 months. Four patients died. Anti-IFN-γ auto-Abs concentration was significantly lower at baseline and decreased over time in the drug-free remission group compared to another group (p = 0.001). C-reactive protein, erythrocyte sedimentation rate and white cell count were found to be useful biomarkers for determining disease activity during follow-up.

Conclusions

Reinfection or relapse of OIs is common despite long-term antimicrobial treatment in patients with anti-IFN-γ auto-Abs. Treatment to modify anti-IFN-γ auto-Abs production may improve long-term outcomes in this patient population.

Tumor mutational profile of triple negative breast cancer patients in Thailand revealed distinctive genetic alteration in chromatin remodeling gene

Background

Triple negative breast cancer (TNBC) is a breast cancer subtype characterized by absence of both hormonal receptors and human epithelial growth factor receptor 2 (HER2). TNBC accounts for 15–20% of breast cancer. TNBC is associated with more aggressive disease and worse clinical outcome. Though the underlying mechanism of TNBC is currently unclear, the heterogeneity of clinical characteristics in various population may relate to the difference in tumor mutational profile. There were studies on TNBC gene mutations in various ethnic groups but the tumor genome data on Thai TNBC patients is currently unknown. This study aims to investigate mutational profile of Thai TNBC.

Methods

The patients were Thai individuals who were diagnosed with primary breast carcinoma between 2014 and 2017. All surgically removed primary tumor tissues were carefully examined by pathologists and archived as formalin-fixed paraffin-embedded tumor. TNBC was defined by absence of hormonal receptors and HER2 by immunohistochemistry. Genomic DNA was extracted, enriched and sequenced of all exomes on the Illumina HiSeq. Genomic data were then processed through bioinformatics platform to identify genomic alterations and tumor mutational burden.

Results

A total of 116 TNBC patients were recruited. Genomic analysis of TNBC samples identified 81,460 variants, of which 5,906 variants were in cancer-associated genes. The result showed that Thai TNBC has higher tumor mutation burden than previously reported data. The most frequently mutated cancer-associated gene was TP53 similar to other TNBC cohorts. Meanwhile KMT2C was found to be more commonly mutated in Thai TNBC than previous studies. Mutational profile of Thai TNBC patients also revealed difference in many frequently mutated genes when compared to other Western TNBC cohorts.

Conclusion

This result supported that TNBC breast cancer patients from various ethnic background showed diverse genome alteration pattern. Although TP53 is the most commonly mutated gene across all cohorts, Thai TNBC showed different gene mutation frequencies, especially in KMT2C. In particular, the cancer gene mutations are more prevalent in Thai TNBC patients. This result provides important insight on diverse underlying genetic and epigenetic mechanisms of TNBC that could translate to a new treatment strategy for patients with this disease.

Derivation of an induced pluripotent stem cell line (MUSIi004-A) from dermal fibroblasts of a 48-year-old spinocerebellar ataxia type 3 patient

Dermal fibroblasts were obtained from a 48-year-old female patient with spinocerebellar ataxia type 3 (SCA3). Fibroblasts were reprogrammed by nucleofection with episomal plasmids, carrying L-MYC, LIN28, OCT4, SOX2, KLF4, EBNA-1 and shRNA against p53. The SCA3 patient-specific iPSC line, MUSIi004-A, was characterized by immunofluorescence staining to verify the expression of pluripotent markers. The iPSC line exhibited an ability to differentiate into three germ layers by embryoid body (EB) formation. Karyotypic analysis of the MUSIi004-A line was normal. The mutant allele was still present in the iPSC line. This iPSC line represents a useful tool for studying neurodegeneration in SCA3.

Molecular investigation by whole exome sequencing revealed a high proportion of pathogenic variants among Thai victims of sudden unexpected death syndrome

Introduction

Sudden unexpected death syndrome (SUDS) is an important cause of death in young healthy adults with a high incident rate in Southeast Asia; however, there are no molecular autopsy reports about these victims. We performed a combination of both a detailed autopsy and a molecular autopsy by whole exome sequencing (WES) to investigate the cause of SUDS in Thai sudden death victims.

Materials and methods

A detailed forensic autopsy was performed to identify the cause of death, followed by a molecular autopsy, in 42 sudden death victims who died between January 2015 and August 2015. The coding sequences of 98 SUDS-related genes were sequenced using WES. Potentially causative variants were filtered based on the variant functions annotated in the dbNSFP database. Variants with inconclusive clinical significance evidence in ClinVar were resolved with a variant prediction algorithm, metaSVM, and the frequency data of the variants found in public databases, such as the 1000 Genome Project, ESP6500 project, and the Exome Aggregation Consortium (ExAc) project.

Results

Combining both autopsy and molecular autopsy enabled the potential identification of cause of death in 81% of the cases. Among the 25 victims with WES data, 72% (18/25) were found to have potentially causative SUDS mutations. The majority of the victims had at a mutation in the TTN gene (8/18 = 44%), and only one victim had an SCN5A mutation.

Conclusions

WES can help to identify the genetic causes in victims of SUDS and may help to further guide investigations into their relatives to prevent additional SUDS victims.

Factors associated with acquired Anti IFN- γ autoantibody in patients with nontuberculous mycobacterial infection

Background

The clinical syndrome of disseminated nontuberculous mycobacterial (NTM) infection in patients who were previously healthy is now well recognized to be associated with an acquired autoantibody to Interferon gamma (Anti IFN- γ autoantibody). However, the risk factors of this syndrome remain unknown.

Method

We performed an unmatched case control study among patients with NTM diseases who were diagnosed and treated at Siriraj Hospital, Bangkok, Thailand. Anti-IFN autoantibody was detected by enzyme-linked immunosorbent assay (ELISA) method. Cases were patients with NTM diseases and detectable anti IFN- γ autoantibody. Controls were randomly selected from those with undetectable anti IFN- γ autoantibody. Data from both groups including demographic data, clinical presentation, laboratory results, other risk factors and HLA genotypes were collected. Univariate and multivariate analyses were performed to identify independent risk factors for this syndrome.

Results

70 cases (mean age 50 ± 11 years) and 70 controls (mean age 58 ± 18 years) were enrolled into the study. Mycobacterial abscessus was the most common NTM pathogen found in both groups (72.9% in cases and 41.4% in controls respectively). However, disseminated NTM disease was significantly more common in cases (92.9%) than in the controls (14.3%, p<0.001). Binary logistic regression analysis showed that previous OIs (adjusted OR14.87, 95% CI 2.36–93.86), birthplace outside Central region (adjusted OR 19.19, 95% CI 3.86–95.35), lack of comorbidities lead to immunosuppression, such as HIV infection or diabetes mellitus (adjusted OR 23.68, 95% CI 4.01–139.94), and presence of HLA DRB1*15/16 (adjusted OR 153.28, 95% CI 16.87–139.88) were independent factors associated with this syndrome.

Conclusion

Patients with NTM disease associated with anti IFN- γ autoantibody are almost always previously healthy and HIV negative. Most of these patients presented with disseminated NTM disease with generalized lymphadenitis and often with reactive skin lesions. Factors associated with detectable anti IFN- γ autoantibody are HLA-DRB1 and DQB1 alleles, and history of previous OIs in patients without comorbidity that leads to immunosuppression. Further studies are needed to better understand these associations and to improve the treatment outcome.

Revised Ghent Criteria is Comparable to Original Diagnostic Criteria for Marfan Syndrome with Increased Ability to Clinically Diagnose Related Disorders

BACKGROUND

Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder with major features in cardiovascular ocular and skeletal systems. Due to its genetic heterogeneity and variable expressivity, Ghent nosology was established for clinical diagnosis of MFS. In 2010, Ghent diagnostic criteria were revised to better diagnose MS and categorize its related disorders. There is no previous clinical comparison between the original and revised Ghent criteria for diagnosis of MFS in Thai patients.

OBJECTIVE

To compare application and efficacy of Ghent and revised Ghent criteria in adult Thai patients with clinical suspicion of MFS.

MATERIAL AND METHOD

This study was a retrospective analysis of patients with clinical suspicion of MFS who attended the Medical Genetics Clinic, Siriraj Hospital between January 2003 and December 2013. Patients were clinically examined for diagnosis of MFS using both the Ghent and revised Ghent criteria. Multidisciplinary data, including physical examination, echocardiography, slit-lamp examination, and genetic testing, were analyzed.

RESULTS

Clinical and genetic data of 138 (77 males and 61 females) individuals with clinical suspicion of MFS were reviewed The most common presentation was cardiovascular manifestation. Of 92 patients diagnosed as MFS by original Ghent nosology 70 of those patients (76.1%) were also diagnosed as MFS by revised Ghent criteria. Forty-eight of 138 patients (34.8%) had undergone genetic testing, with FBN1 mutations detected in 23 patients. Twenty-two patients with detectable FBN1 mutations fulfilled both the Ghent and revised Ghent criteria. Of 22 patients whose diagnoses were not fulfilled by revised Ghent nosology, most were due to inadequate systemic score (SS). The use of revised Ghent nosology also facilitated improved diagnosis of MFS-related disorders.

CONCLUSION

Revised Ghent nosology has further differentiated MFS from other MFS-related disorders and has further expanded the classification of MFS-related disorders. Genetic testing of FBN1 helps physicians to more accurately diagnose patients with MFS and related disorders.

HLA-DRB1 and HLA-DQB1 Are Associated with Adult-Onset Immunodeficiency with Acquired Anti-Interferon-Gamma Autoantibodies

Recently a newly identified clinical syndrome of disseminated non-tuberculous mycobacterial diseases (with or without other opportunistic infections in adult patients who were previously healthy, has been recognized in association with an acquired autoantibody to interferon-gamma. This syndrome is emerging as an important cause of morbidity and mortality, especially among people of Asian descent. Trigger for the production of this autoantibody remains unknown, but genetic factors are strongly suspected to be involved. We compared HLA genotyping between 32 patients with this clinical syndrome, and 38 controls. We found that this clinical syndrome was associated with very limited allele polymorphism, with HLA-DRB1 and DQB1 alleles, especially HLA-DRB1*15:01, DRB1*16:02, DQB1*05:01 and DQB1*05:02. Odds ratio of DRB1*15:01, DRB1*16:02, DQB1*05:01 and DQB1*05:02 were 7.03 (95% CI, 2.18–22.69, P<0.0001, 9.06 (95% CI, 2.79–29.46, P<0.0001), 6.68 (95% CI, 2.29–19.52, P = 0.0004), and 6.64 (95% CI, 2.30–19.20, P = 0.0004), respectively. Further investigation is warranted to provide better understanding on pathogenesis of this association.

Novel Mutation of the TINF2 Gene in a Patient with Dyskeratosis Congenita

Dyskeratosis congenita (DKC) is a rare inherited disease that is characterized by abnormal skin pigmentation, nail dystrophy and mucosal leukoplakia. DKC is caused by an abnormality in a component of the telomerase and shelterin complexes. TINF2 encodes a protein in the shelterin complex and TERC encodes a component of the telomerase complex. Mutations of both genes have been associated with DKC. This study examined mutations in TINF2.

Mycophenolic acid AUC in Thai kidney transplant recipients receiving low dose mycophenolate and its association with UGT2B7 polymorphisms

Background

Despite use of a lower mycophenolate dose in Thai kidney transplant patients, acceptable graft and patient outcomes can be achieved. We therefore examined the pharmacokinetics of mycophenolic acid (MPA) by area under the curve (AUC) and investigated genetic contribution in mycophenolate metabolism in this population.

Methods

Kidney transplant recipients with stable graft function who were receiving mycophenolate mofetil 1,000 mg/d in combination with either cyclosporine or tacrolimus, and prednisolone were studied. The MPA concentration was measured by fluorescence polarization immunoassay (FPIA), at predose and 1, 1.5, 2, 4, 6, 8, 10, and 12 hours after dosing. Genetic polymorphisms in UGT1A8, UGT1A9, and UGT2B7 were examined by denaturing high-performance liquid chromatography (DHPLC)-based single-base extension (SBE) analysis.

Results

A total 138 patients were included in study. The mean AUC was 39.49 mg-h/L (28.39–89.58 mg-h/L), which was in the therapeutic range. The correlation between the predose MPA concentration and AUC was poor. The mean AUC in the tacrolimus group was higher than that in the cyclosporine group. Polymorphisms in UGT2B7 showed significant association with AUC.

Conclusion

Most of our patients with reduced mycophenolate dose had the AUC within the therapeutic range. Genetic polymorphisms in UGT2B7 may play a role in MPA metabolism in Thai kidney transplant patients.

A Novel Mutation of the GNE Gene in Distal Myopathy with Rimmed Vacuoles: A Case with Inflammation

Distal myopathy with rimmed vacuoles (DMRV) is an autosomal recessive or sporadic early adult-onset myopathy caused by mutations in the UDP-N-acetylglucosamine 2-epimerase and N-acetylmannosamine kinase (GNE) gene. Characteristic pathologic features of DMRV are rimmed vacuoles on muscle biopsy and tubulofilamentous inclusion in ultrastructural study. Presence of inflammation in DMRV is unusual. We report a sporadic case of DMRV in a 40-year-old Thai man who presented with slowly progressive distal muscle weakness. Gene analysis revealed a compound heterozygous mutation of the GNE gene including a novel mutation c.1057A>G (p.K353E) and a known mutation c.2086G>A (p.V696M). The latter is the most common mutation in Thai DMRV patients. The muscle pathology was compatible with DMRV except for focal inflammation.

Unusual presentation as an adult onset painful myopathy in a Thai patient with Becker muscular dystrophy

A Thai 37-years-old man presented with adult onset progressive proximal muscle weakness and generalized myalgia. Family history showed similar symptoms in several male relatives, compatible with X-linked recessive inheritance. Electromyography suggested myopathic process. Serum creatine kinase was highly elevated. Diagnosis of Becker muscular dystrophy (BMD) was confirmed by genetic testing. His symptoms responded well to steroid treatment. This report is of the first Thai patient with atypical presentation of BMD.

Genetic polymorphism of low-density lipoprotein receptor did not affect treatment outcome of chronic hepatitis C genotype 3

BACKGROUND

The low-density lipoprotein receptor (LDL-R) has been proposed to function as a receptor for the hepatitis C virus (HCV) entry. Polymorphism of LDL-R gene may influence the clearance of virus and response to treatment. This study was conducted to evaluate the association of LDL-R gene polymorphism and the response to antiviral treatment in patients with chronic HCV infection.

MATERIAL AND METHOD

A total of 112 naïve patients with HCV genotype 3 were enrolled in the study. All patients were treated with a combination of pegylated interferon and ribavirin for 24 weeks. Polymerase chain reaction combined with restriction fragment length polymorphism was used to detect the polymorphism at the LDL-R gene intron 11 loci, including intron1, intron 3.1, intron 3.2, intron 4, intron 6, exon 8, intron 11, intron 13, intron 14 and 3'UTR-2 SNPs in intron 16 region. Comparisons of genotype and allele frequency between responders and nonresponders were analyzed.

RESULTS

Patients had a mean age of 54 years and 43% were male. Mean HCVRNA viral load and alanine aminotransferase level were 6.3 log, IU/mL and 100 IU/L, respectively. Sustained virological response, relapse and no response were documented in 68.7%, 17.9% and 13.4%, respectively. Baseline characteristics including age, sex, body weight, aminotransferase levels and HCV RNA viral load were similar between responders and nonresponders. No statistical difference was found for either genotype distribution or allele frequency among responders and nonresponders.

CONCLUSION

This study did not provide the evidence for a role of LDL-R polymorphism the response to antiviral treatment in patients with HCV genotype 3. This indicates that a genetic component via the LDL-R may not control HCV treatment outcome in HCV genotype 3

Can we predict final outcome of internal medicine residents with in-training evaluation

OBJECTIVE

To assess the predictive value of in-training evaluation for determining future success in the internal medicine board certifying examination.

MATERIAL AND METHOD

Ninety-seven internal medicine residents from Faculty of Medicine Siriraj Hospital who undertake the Thai Board examination during the academic year 2006-2008 were enrolled. Correlation between the scores during internal medicine rotation and final scores in board examination were then examined.

RESULTS

Significant positive linear correlation was found between scores from both written and clinical parts of board certifying examination and scores from the first-year summative written and clinical examinations and also the second-year formative written examination (r = 0.43-0.68, p < 0.001). Monthly evaluation by attending staffs was less well correlated (r = 0.29-0.36) and the evaluation by nurses or medical students demonstrated inverse relationship (r = -0.2, p = 0.27 and r = -0.13, p = 0.48).

CONCLUSION

Some methods of in-training evaluation can predict successful outcome of board certifying examination. Multisource assessments cannot well extrapolate some aspects of professional competences and qualities.

Six novel ATP7B mutations in Thai patients with Wilson disease

WD is an autosomal recessive disorder of copper transport resulting in excessive copper deposition in the liver and brain. It is caused by defects of ATP7B encoding a copper transporting P-type ATPase. To identify the mutations in ATP7B in Thai patients with WD, DHPLC analysis was applied to detect mutations and polymorphisms of the entire ATP7B gene in 19 Thai patients with WD. Mutations in ATP7B were identified in 14 of 19 patients: 2 homozygotes, 8 compound heterozygotes and 4 heterozygotes. Eighteen mutations distributed throughout the entire coding region of ATP7B gene including 11 missense, 3 nonsense, 1 splice-site, 1 deletion and 2 insertions. Of 18 different mutations identified, 6 were found to be novel. Twelve single nucleotide polymorphisms (SNPs) were also identified and two SNPs have not yet previously been reported. Segregation analysis using DHPLC analysis showed mutation transmission patterns within each family of Thai patients with WD. Mutations in ATP7B in Thai patients with WD are worth adding into the public database for genetic epidemiology and population genetics.

A 47, XXY patient and Xq21.31 duplication with features of Prader-Willi syndrome: results of array-based comparative genomic hybridization

A man diagnosed with 47, XXY during childhood presents an appearance similar to that of Prader-Willi syndrome with hypogonadism and gynecomastia, developmental delay, and short stature and obesity. Array-based comparative genomic hybridization revealed duplication at Xq21.31 in addition to his abnormal karyotype. This duplication was also found in his mother who appeared normal. We raise the possibility that the phenotype in this patient is a combination of both extra X chromosome and Xq21 duplication.

Clinical presentation and echocardiographic findings of Thai patients with Marfan syndrome

OBJECTIVE

Marfan syndrome is an inherited disorder with systemic connective tissue involvement. The condition is clinically diverse and extremely pleiotropic. Though several articles had been published, no data from Thai individuals has ever been reported. Here we presented clinical manifestations and echocardiographic findings of Thai patients with Marfan syndrome.

MATERIAL AND METHOD

Clinical and echocardiographic data were collected from series of Thai index cases with diagnosis of Marfan syndrome at Siriraj Hospital between 1995 and 2009. Demographic data, clinical presentations, and echocardiographic data were reviewed and analyzed.

RESULTS

Fifty individuals and thirty echocardiograms were identified. Thirty eight individuals (76%) fulfilled clinical criteria for definite Marfan syndrome and twelve individuals (24%) were incomplete Marfan syndrome. The majority of those individuals had significant organ involvement including dilatation of ascending aorta (78%), ectopia lentis (54%), and skeletal involvement (96%).

CONCLUSIONS

In summary, this is the first report of clinical manifestation and echocardiographic findings of Thai patients with Marfan syndrome.

Fumarate hydratase enzyme activity in lymphoblastoid cells and fibroblasts of individuals in families with hereditary leiomyomatosis and renal cell cancer

BACKGROUND

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is the autosomal dominant heritable syndrome with predisposition to development of renal cell carcinoma and smooth muscle tumours of the skin and uterus.

OBJECTIVE

To measure the fumarate hydratase (FH) enzyme activity in lymphoblastoid cell lines and fibroblast cell lines of individuals with HLRCC and other familial renal cancer syndromes.

METHODS

FH enzyme activity was determined in the whole cell, cytosolic, and mitochondrial fractions in 50 lymphoblastoid and 16 fibroblast cell lines including cell lines from individuals with HLRCC with 16 different mutations.

RESULTS

Lymphoblastoid cell lines (n = 20) and fibroblast cell lines (n = 11) from individuals with HLRCC had lower FH enzyme activity than cells from normal controls (p<0.05). The enzyme activity in lymphoblastoid cell lines from three individuals with mutations in R190 was not significantly different from individuals with other missense mutations. The cytosolic and mitochondrial FH activity of cell lines from individuals with HLRCC was reduced compared with those from control cell lines (p<0.05). There was no significant difference in enzyme activity between control cell lines (n = 4) and cell lines from affected individuals with other hereditary renal cancer syndromes (n = 22).

CONCLUSIONS

FH enzyme activity testing provides a useful diagnostic method for confirmation of clinical diagnosis and screening of at-risk family members.

Novel mutations in FH and expansion of the spectrum of phenotypes expressed in families with hereditary leiomyomatosis and renal cell cancer

BACKGROUND

Hereditary leiomyomatosis and renal cell cancer (HLRCC; OMIM 605839) is the predisposition to develop smooth muscle tumours of the skin and uterus and/or renal cancer and is associated with mutations in the fumarate hydratase gene (FH). Here we characterise the clinical and genetic features of 21 new families and present the first report of two African-American families with HLRCC.

METHODS

Using direct sequencing analysis we identified FH germline mutations in 100% (21/21) of new families with HLRCC.

RESULTS

We identified 14 germline FH mutations (10 missense, one insertion, two nonsense, and one splice site) located along the entire length of the coding region. Nine of these were novel, with six missense (L89S, R117G, R190C, A342D, S376P, Q396P), one nonsense (S102X), one insertion (111insA), and one splice site (138+1G>C) mutation. Four unrelated families had the R58X mutation and five unrelated families the R190H mutation. Of families with HLRCC, 62% (13/21) had renal cancer and 76% (16/21) cutaneous leiomyomas. Of women FH mutation carriers from 16 families, 100% (22/22) had uterine fibroids. Our study shows that expression of cutaneous manifestations in HLRCC ranges from absent to mild to severe cutaneous leiomyomas. FH mutations were associated with a spectrum of renal tumours. No genotype-phenotype correlations were identified.

CONCLUSIONS

In combination with our previous report, we identify 31 different germline FH mutations in 56 families with HLRCC (20 missense, eight frameshifts, two nonsense, and one splice site). Our FH mutation detection rate is 93% (52/56) in families suspected of HLRCC.