Portal de Periódicos da CAPES

A second-site mutation in the initiation codon ofWAS (WASP) results in expansion of subsets of lymphocytes in an Wiskott-Aldrich syndrome patient

2006; Wiley; Volume: 27; Issue: 4 Linguagem: Inglês

10.1002/humu.20308

1098-1004

Wei Du, Satoru Kumaki, Toru Uchiyama, Akihiro Yachie, Chung Yeng Looi, S. Kawai, Masayoshi Minegishi, Narayanaswamy Ramesh, Raif S. Geha, Yoji Sasahara, Shigeru Tsuchiya,

Cell Image Analysis Techniques

Wiskott-Aldrich syndrome (WAS) is caused by mutations in the gene encoding WAS protein (WASP ). Recently, somatic mosaicism caused by reversions or second-site mutations has been reported in some inherited disorders including WAS. In this article, we describe somatic mosaicism in a 15-year-old WAS patient due to a second-hit mutation in the initiation codon. The patient originally had a single-base deletion (c.11delG; p.G4fsX40) in the WAS (WASP) gene, which resulted in a frameshift and abrogated protein expression. Subsequently, a fraction of T and natural killer (NK) cells expressed a smaller WASP, which binds to its cellular partner WASP-interacting protein (WIP). The T and NK cells were found to have an additional mutation in the initiation codon (c.1A>T; p.M1_P5del). The results strongly suggest that the smaller WASP is translated from the second ATG downstream of the original mutation, and not only T cells but also NK cells carrying the second mutation acquired a growth advantage over WASP negative counterparts. To our knowledge, this is the first report describing somatic mosaicism due to a second-site mutation in the initiation codon of any inherited disorders.