Missense mutation in a patient with X-linked dyskeratosis congenita.

We report the case of a 40-year-old male patient with dyskeratosis congenita(DKC). Sequencing of the DKC1 gene revealed an inherited missense mutation in base 1050 (GC), changing methionine to isoleucine. This is the third description of a mutation in codon 350 (exon 11), changing a very well conserved amino acid in the pseudouridine synthase (PUA) domain of dyskerin.