발달 지연으로 내원한 Cystathionine 뇨증 1례

A Case of Cystathioninuria with Delayed Development

γ-cystathionase 결핍으로 인해 생긴 cystathioninuria는 상염색체 열성 유전질환으로, 다양한 임상양상을 보이며, 이 질환에 특징적으로 연관된 임상양상은 없는 것으로 추측되며, 다수에서 pyridoxine 경구 투여에 의해 호전된다. 저자들은 발달 지연을 주소로 내원하여 소변 아미노산 분석 검사 결과 시스틴뇨증으로 진단되고 pyridoxine 경구 투여로 호전된 1례를 경험하고, 우리나라에서 첫 증례라고 사료되어 이에 문헌 고찰과 함께 보고하는 바이다.

Cystathionine is well-known intermediate in the metabolism of methionine. It is cleaved to cysteine and homoserine by γ-cystathionase. This enzyme utilize pyridoxal 5'-phosphate as coenzyme. γ-cystathionase deficiency leads to persistent excretion of large amount of cystathionine in urine, as well as to accumulation of cystathionine in body tissues and fluids. It is inherited as an autosomal recessive trait and shows wide variety of clinical manifestations. No clinical abnormality seems to be specifically associated with γ-cystathionase deficiency. The majority of patients responded to high dose administration of pyridoxine. We report the first case of cystathioninuric patient in Korea, 19 months of female with developmental delay. In brain MRI, there was generalized mild brain atrophy. There were several times of brief paroxysmal generalized polyspike and wave discharges in electroencephalography(EEG). In amino acid analysis of urine, there was elevated level of cystathionine. She was treated with high dose of pyridoxine. In follow up analysis of urinary amino acid, the cystathionine level was markedly decreased to normal range, and EEG was normalized. Her development shows improvement.