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

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

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)370-375
Number of pages6
JournalHuman mutation
Volume27
Issue number4
DOIs
Publication statusPublished - 2006 Apr 1

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)

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