Marfan症候群として治療中，躁状態・反応性もうろう状態を呈したホモシスチン尿症の女児例

A 14-Year-Old Girl with Homocystinuria, Affective Disorder, and Reactive Twilight State who had been long followed under the diagnosis of Marfan's Syndrome with Mental Retardation

　【抄録】　ホモシスチン尿症は，新生児マス・スクリーニングの対象となっている先天性代謝異常症に含まれる常染色体劣性遺伝の極めて稀な疾患である。また本疾患はしばしば水晶体偏位や四肢細長，クモ状指など，Marfan症候群に類似する臨床症状を示すことから，両者の鑑別が問題になる。今回我々は，新生児スクリーニング（ガスリー法）で発見されず，小児期から精神発達遅滞を伴うMarfan症候群としての治療および経過観察を受けてきて，14歳時に躁状態ともうろう状態を発症したため当科を受診し，その後の精査でシスタチオニンβ-合成酵素欠損によるホモシスチン尿症と診断された1女児例を経験したので報告した。

　Homocystinuria is an inborn error of methionine metabolism with autosomal recessive inheritance. A nationwide neonatal metabolic screening program has been performed in Japan since 1977, and 18 cases of homocystinuria have been detected. It is, however, still important for all clinicians to differentiate homocystinuria and Marfan's syndrome, for both diseases resemble each other clinically e. g. ectopia lentis and skeletal abnormalities. A 14year-old girl with homocystinuria caused by cystathionine betasynthase deficiency presented bipolar affective disorder and reactive twilight state. She had not been detected by the neonatal mass screening and had been long followed under the diagnosis of Marfan's syndrome with mental retardation. Quantitative plasma aminoacid analysis should be performed in any cased suspected of Marfan's syndrome especially with mental retardation.