Sepiapterin reductase deficiency: Report of 5 new cases

Abstract

Background: Sepiapterin reductase deficiency is a rare, under-recognized, autosomal recessively inherited disorder of neurotransmitter metabolism.

Case report: Five 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.

Conclusion: Our cases illustrate the difficulties in the diagnosis of sepiapterin reductase deficiency in infancy, and the importance of early recognition and management.

Keywords: CSF neurotransmitters; Hypotonia; Oculogyric crisis; Sepiapterin reductase deficiency.