Journal of Genetic Medicine  2009;6(2):170-174

A Case of Dihydropteridine Reductase Deficiency.

Se Jung OH 1 ; Yong Hee HONG ; Yong Wha LEE ; Seung Tae LEE ; Chang Seok KI ; Dong Hwan LEE

Affiliations

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Keywords

Tetrahydrobiopterin; Dihydropteridine reductase deficiency

Country

Republic of Korea

Language

Korean

Abstract

Tetrahydrobiopterin (BH4) deficiency is caused by mutations in genes encoding enzymes involved in the synthesis and regeneration of BH4. The condition is usually accompanied by hyperphenylalaninemia (HPA) and deficiency of neurotransmitter precursors L-dopa and 5-hydroxytryptophan. BH4 deficiency is much rarer than classical phenylketonuria. Dihydropteridine reductase (DHPR) deficiency, an autosomal recessive genetic disorder, is a cause of malignant hyperphenylalaninemia due to BH4 deficiency. When left untreated, DHPR deficiency leads to neurologic deterioration at the age of 4 or 5 months, including psychomotor retardation, tonicity disorders, drowsiness, irritability, abnormal movements, hyperthermia, hypersalivation, and difficulty swallowing. Treatment of DHPR deficiency should be initiated as early as possible with BH4 supplementation and replacement of the neurotransmitter precursors L-dopa and 5-hydroxytryptophan. We report the first case of DHPR deficiency in Korea, a child diagnosed at 9 years of age by genetic testing.