A Case of Dihydropteridine Reductase Deficiency

Dihydropteridine Reductase 결핍증 1례

Tetrahydrobiopterin ($BH_4$) deficiency is caused by mutations in genes encoding enzymes involved in the synthesis and regeneration of $BH_4$. The condition is usually accompanied by hyperphenylalaninemia (HPA) and deficiency of neurotransmitter precursors L-dopa and 5-hydroxytryptophan. $BH_4$ deficiency is much rarer than classical phenylketonuria. Dihydropteridine reductase (DHPR) deficiency, an autosomal recessive genetic disorder, is a cause of malignant hyperphenylalaninemia due to $BH_4$ 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 $BH_4$ 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.

저자들은 생후 3개월에 전형적인 페닐케톤뇨증으로 진단받고 식사요법을 유지하였으나 지연된 발달 소견 및 지능 저하를 보이고 경련 증상이 있었던 9세 남자 환아에서 효소 검사와 유전자분석으로 dihydropterine reductase (DHPR) 결핍증을 진단하였다. 그리고 $BH_4$, 신경전달물질 전구체 투여 및 엽산 보충으로 DHPR 결핍증을 치료한 1례를 경험하였기에 문헌고찰과 함께 보고한다.