History and admission findings: A 24-year-old man with thrombocytopenia was
referred for surgical resection of a bleeding polyp of the sigmoid. Examin
ation showed a small haematoma and petechiae on both lower legs. The patien
t reported that several male family members also had a thrombocytopenic ble
eding tendency.
Investigations: Laboratory tests revealed thrombocytopenia (4000 platelets/
ml, with small platelets: mean platelet volume [MPV] 5.6 mi). Serum immunog
lobulins were normal. A mutation in the Wisskott-Aldrich (W-A) protein gene
(intron 7+5 G-->A) was demonstrated both in the patient and his 26-year-ol
d brother.
Diagnosis, treatment and course: The diagnosis of W-A syndrome was made and
, with perioperative administration of platelets, the polyp was resected wi
thout complication.
Conclusion: Most patients with the W-A syndrome die by the time they are ag
ed 10 years, unless appropriate treatment is given. This patient and his br
other had a mutation of the W-A protein gene that unusually was in an intro
n rather than in an exon. Structurally normal W-A proteins were still being
formed. This may explain the mild course and late onset of the disease.