Case studySepiapterin reductase deficiency: Report of 5 new cases

•Sepiapterin reductase deficiency is a treatable neurometabolic condition.•It should be considered in patients with motor/cognitive delay, dystonia, or oculogyric crisis.•It contributes to better recognition of the clinical pattern of sepiapterin reductase deficiency.

BackgroundSepiapterin reductase deficiency is a rare, under-recognized, autosomal recessively inherited disorder of neurotransmitter metabolism.Case reportFive new patients from 3 unrelated Saudi consanguineous families are reported. Symptoms began at 6 months, with delay to diagnosis averaging 8 years. All 5 patients presented with severe symptoms including axial hypotonia, dystonia, and cognitive impairment, associated with hyper-reflexia (4 patients), spasticity (4 patients), bulbar dysfunction (4 patients), and oculogyric crisis (2 patients) with diurnal fluctuation and sleep benefit. Cerebrospinal fluid neurotransmitters analysis showed a typical pattern with increased sepiapterin and increased 7,8-dihydrobiopterin. Analysis of the SPR gene identified 3 novel mutations: c.1A > G, c.370T > C, and c.527C > T. Patient one, with early diagnosis, is currently developing within the normal range. The 4 other patients showed significant improvement in their motor function, but only mild improvement in their cognitive dysfunction.ConclusionOur cases illustrate the difficulties in the diagnosis of sepiapterin reductase deficiency in infancy, and the importance of early recognition and management.