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Paternal mosaicism of an STXBP1 mutation in OS
Author(s) -
Saitsu H,
Hoshino H,
Kato M,
Nishiyama K,
Okada I,
Yoneda Y,
Tsurusaki Y,
Doi H,
Miyake N,
Kubota M,
Hayasaka K,
Matsumoto N
Publication year - 2011
Publication title -
clinical genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 102
eISSN - 1399-0004
pISSN - 0009-9163
DOI - 10.1111/j.1399-0004.2010.01575.x
Subject(s) - biology , germline mosaicism , genetics , nonsense mutation , mutation , germline mutation , somatic cell , buccal swab , exon , microbiology and biotechnology , missense mutation , gene
Saitsu H, Hoshino H, Kato M, Nishiyama K, Okada I, Yoneda Y, Tsurusaki Y, Doi H, Miyake N, Kubota M, Hayasaka K, Matsumoto N. Paternal mosaicism of an STXBP1 mutation in OS. Ohtahara syndrome (OS) is one of the most severe and earliest forms of epilepsy. We have recently identified that the de novo mutations of STXBP1 are important causes for OS. Here we report a paternal somatic mosaicism of an STXBP1 mutation. The affected daughter had onset of spasms at 1 month of age, and interictal electroencephalogram showed suppression‐burst pattern, leading to the diagnosis of OS. She had a heterozygous c.902+5G>A mutation of STXBP1 , which affects donor splicing of exon 10, resulting in 138‐bp insertion of intron 10 sequences in the transcript. The mutant transcript had a premature stop codon, and was degraded by nonsense‐mediated mRNA decay in lymphoblastoid cells derived from the patient. High‐resolution melting analysis of clinically unaffected parental DNAs suggested that the father was somatic mosaic for the mutation, which was also suggested by sequencing. Cloning of PCR products amplified with the paternal DNA samples extracted from blood, saliva, buccal cells, and nails suggested that 5.3%, 8.7%, 11.9%, and 16.9% of alleles harbored the mutation, respectively. This is a first report of somatic mosaicism of an STXBP1 mutation, which has implications in genetic counseling of OS.