We describe a patient with myelodysplastic syndrome with monosomy 7 pr
esenting with a T-cell defect. He suffered from infections from the ag
e of 10 years, when a CD4 deficiency and impaired lymphoproliferative
responses in vitro were found. The only symptom of a myelodysplastic s
yndrome at that time was thrombocytopenia with giant platelets. Monoso
my 7 was found in the bone marrow cells. At the age of 11 years he dev
eloped other characteristics of monosomy 7 including splenomegaly and
anaemia. Some months later leukaemia was diagnosed. Conclusion In non-
HIV CD4 deficiency myelodysplastic syndrome has to be considered.