Two brothers with dystonia and slight MRI changes in the basal ganglia had
normal urinary glutaric acid excretion, but slightly increased 3-hydroxyglu
tarate and conjugated glutarate excretions. Both siblings have high residua
l glutaryl-CoA dehydrogenase activity, and are compound heterozygotes for t
wo mutations - R227P and V400M - reported to be disease-causing in patients
with glutaric aciduria type I.