Dihydropteridine reductase deficiency in a large consanguineous Tunisian family: clinical, biochemical, and neuropathologic findings.

We report the case of a large consanguineous Tunisian family of seven siblings suffering from dihydropteridine reductase deficiency with either typical clinical, biochemical, or autopsy findings. Two cousins also were reported to have the same symptoms. This metabolic disorder is characterized by severe microcephaly, psychomotor regression, and progressive basal ganglia calcifications. Dihydropteridine reductase assay on samples collected from the two brothers still alive did not show measurable activity. The sister and four brothers died between the ages of 3 years and 7 years. A neuropathology study done on the sister showed diffuse demyelination throughout the white matter and spongy vacuolation in the subthalamic nuclei, the superior cerebellar peduncles and the tegmentum tracts of the brain stem. The anterointernal part of the putamen was completely necrotic with nearly total nerve cell loss. Abnormal vascular proliferation and calcification of the walls of small, medium, and large arteries and veins, as well as diffusely scattered pericapillary and isolated calcospherites, were seen in this necrotic region. We think that folate deficiency may be involved in the pathogenesis of the basal ganglia calcification.