Heterozygous mutation in 5?-untranslated region of sepiapterin reductase gene (SPR) in a patient with dopa-responsive dystonia

Abstract
The search for mutations in genes coding for components of the biopterin pathway other than GTPCH1 revealed a mutation in the gene coding for sepiapterin reductase ( SPR) in 1 of 95 patients with GCH1-negative dopa-responsive dystonia (DRD). The mutation detected in SPR is a G→A transition at position –13 of the untranslated region of the gene. This resulted in drastically reduced activity of sepiapterin reductase in the patient’s fibroblasts. The findings indicate that haploinsufficiency of SPR can be a rare cause of DRD.