Background: Wiskott-Aldrich syndrome is a rare X-linked immunodeficiency disorder with a variable phenotype.
Case characteristics: 3.5-year-old boy diagnosed with Wiskott-Aldrich syndrome.
Observation: Unusual and persistent thrombocytopenia with increased platelet volume (>10fL). He did not exhibit characteristic clinical and laboratory finding for the syndrome.
Outcome: Maternally inherited causative mutation in the exon 2 of the WAS gene was disclosed.
Message: This is a need for multidisciplinary assessment of patients with congenital or early infantile thrombocytopenia, including testing for mutations of the WAS gene in all unexplained cases even in the absence of characteristic microthrombocytopenia.