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Quantification of transmission risk in a male patient with a FLNB mosaic mutation causing Larsen syndrome: Implications for genetic counseling in postzygotic mosaicism cases
Author(s) -
Bernkopf Marie,
Hunt David,
Koelling Nils,
Morgan Tim,
Collins Amanda L.,
Fairhurst Joanna,
Robertson Stephen P.,
Douglas Andrew G. L.,
Goriely Anne
Publication year - 2017
Publication title -
human mutation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 162
eISSN - 1098-1004
pISSN - 1059-7794
DOI - 10.1002/humu.23281
Subject(s) - biology , germline mosaicism , buccal swab , genetics , mutation , genetic counseling , germline mutation , somatic cell , sperm , gene
We report the case of a male patient with Larsen syndrome found to be mosaic for a novel point mutation in FLNB in whom it was possible to provide evidence‐based personalized counseling on transmission risk to future offspring. Using dideoxy sequencing, a low‐level FLNB c.698A>G, encoding p.(Tyr233Cys) mutation was detected in buccal mucosa and fibroblast DNA. Mutation quantification was performed by deep next‐generation sequencing (NGS) of DNA extracted from three somatic tissues (blood, fibroblasts, saliva) and a sperm sample. The mutation was detectable in all tissues tested, at levels ranging from 7% to 10% (mutation present in ∼20% of diploid somatic cells and 7% of haploid sperm), demonstrating the involvement of both somatic and gonadal lineages in this patient. This report illustrates the clinical utility of performing targeted NGS analysis on sperm from males with a mosaic condition in order to provide personalized transmission risk and offer evidence‐based counseling on reproductive safety.