Red Cell Size and Uric Acid in Down's Syndrome

The haematological findings in 113 cases of Down's syndrome have been compared with those in 106 age and sex matched control subjects from the same residential institution. The average value for MCV was higher and the serum vitamin B 12 was lower in the Down's syndrome patients than in the controls. These parameters were not significantly correlated in either group and the patients with low vitamin B 12 levels were shown to absorb the vitamin normally. Plasma and erythrocyte folate levels were normal. The band form counts and serum uric acid concentrations were higher in the Down's syndrome than in the control patients. The bone marrow was examined in 11 of the patients with Down's syndrome and MCV ≥ 99, only one showed megaloblastic changes. The results in the small number of patients with chromosome translocations and mosaicism did not appear to differ from those with the common trisomy‐21 anomaly.