Dihydropyrimidine dehydrogenase deficiency presenting with psychomotor retardation in the first Polish patient.

Dihydropyrimidine dehydrogenase (DPD) deficiency is a rare defect of the first step of the pyrimidine catabolic pathway. Patients with a complete enzyme deficiency may be clinically asymptomatic or suffer from neurological abnormalities of various severity. We report a case of an 8-year-old girl with psychomotor retardation and mild course of the disease. Analysis of urine showed strongly elevated levels of uracil and thymine, and no DPD activity could be detected in peripheral blood mononuclear cells. Sequence analysis of the DPD gene (DPYD) revealed that our patient was homozygous for the common splice-site mutation IVS14+1G > A, which suggest that the carrier status for this mutation may be not rare in the Polish population.