Disorders of somatic mosaicism (DoSM) are a diverse group of syndromic and non-syndromic conditions caused by mosaic variants in genes that regulate cell survival and proliferation. Despite overlap in gene space and technical requirements, few clinical labs specialize in DoSM compared to oncology. We adapted a high-sensitivity next-generation sequencing cancer assay for DoSM in 2014. Some 343 individuals have been tested over the past 5 years, 58% of which had pathogenic and likely pathogenic (P/LP) findings, for a total of 206 P/LP variants in 22 genes. Parameters associated with the high diagnostic yield were: (1) deep sequencing (∼2,000× coverage), (2) a broad gene set, and (3) testing affected tissues. Fresh and formalin-fixed paraffin embedded tissues performed equivalently for identification of P/LP variants (62% and 71% of individuals, respectively). Comparing cultured fibroblasts to skin biopsies suggested that culturing might boost the allelic fraction of variants that confer a growth advantage, specifically gain-of-function variants in PIK3CA. Buccal swabs showed high diagnostic sensitivity in case subjects where disease phenotypes manifested in the head or brain. Peripheral blood was useful as an unaffected comparator tissue to determine somatic versus constitutional origin but had poor diagnostic sensitivity. Descriptions of all tested individuals, specimens, and P/LP variants included in this cohort are available to further the study of the DoSM population.
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http://dx.doi.org/10.1016/j.ajhg.2019.09.002 | DOI Listing |
Alzheimers Dement
December 2024
Xiangya Hospital, Central South University, Changsha, Hunan, China.
Background: Frontotemporal dementia (FTD) exhibits clinical phenotypic and genetic heterogeneity. However, reports on the clinical phenotypic characteristics and the frequency of genetic mutations in large-sample Chinese populations with FTD are lacking. Furthermore, the FTD diagnostic performance of plasma neurodegenerative biomarkers remains unclear.
View Article and Find Full Text PDFBreast Cancer Res Treat
January 2025
Division of Human Genetics, Faculty of Health Sciences, National Health Laboratory Service and University of the Witwatersrand, Johannesburg, 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.
View Article and Find Full Text PDFOphthalmic Genet
January 2025
Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.
Introduction: Due to the recent advent of gene-targeted retinal therapies, the clinical value of high-yield genetic testing for inherited retinal dystrophies (IRDs) has increased considerably. However, diagnostic yield is limited by the reported patient populations in allele frequency databases. This study aimed to determine the effect of race and ethnicity on diagnostic yield in IRDs.
View Article and Find Full Text PDFAnn Med
December 2025
Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive & Genetic Hospital of International Trust and Investment Corporation (CITIC)-Xiangya, Changsha, China.
Objectives: At present, most genetic tests or carrier screening are performed with blood samples, and the known carrier rate of disease-causing variants is also derived from blood. For semen donors, what is really passed on to offspring is the pathogenic variant in their sperm. This study aimed to determine whether pathogenic variants identified in the sperm of young semen donors are also present in their blood, and whether matching results for blood are consistent with results for sperm.
View Article and Find Full Text PDFClin Chem
January 2025
Division of Maternal-Fetal-Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.
Background: Genetic screening has advanced from prenatal cell-free DNA (cfDNA) screening for aneuploidies (cfDNA-ANP) to single-gene disorders (cfDNA-SGD). Clinical validation studies have been promising in pregnancies with anomalies but are limited in the general population.
Methods: Chart review and laboratory data identified pregnancies with cfDNA-SGD screening for 25 autosomal dominant conditions at our academic center.
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