Wiskott-Aldrich syndrome (WAS) is an X-linked recessive disorder characterized by thrombocytopenia, small platelets, eczema, increased susceptibility to infection, and immunodeficiency. Mutations of the Wiskott-Aldrich syndrome protein (WASP) gene are responsible for this severe congenital disease. In this study, we report on a 2-year-old Chinese boy who presented with classic clinical WAS manifestations. By direct sequencing of cDNA and genomic DNA of the patient, we identified a novel mutation: the first nucleotide in exon 8 (G) had been deleted (769delG). This mutation results in two kinds of aberrant mRNA with abnormal splicing and causes frameshift and a stop codon at amino acid 260. Western blotting demonstrated a 28-kDa truncated WAS protein. A maternal study revealed that his mother had a heterozygous genotype, but showed normal WASP expression.