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Classical homocystinuria, also known as cystathionine beta synthase deficiency or CBS deficiency, is an inherited disorder of the metabolism of the amino acid methionine, often involving cystathionine beta synthase. It is an inherited autosomal recessive trait, which means a child needs to inherit a copy of the defective gene from both parents to be affected. ==Signs and symptoms== This defect leads to a multi-systemic disorder of the connective tissue, muscles, central nervous system (CNS), and cardiovascular system. Homocystinuria represents a group of hereditary metabolic disorders characterized by an accumulation of the amino acid homocysteine in the serum and an increased excretion of homocysteine in the urine. Infants appear to be normal and early symptoms, if any are present, are vague. Signs and symptoms of homocystinuria that may be seen include the following: * A family history of homocystinuria * Flush across the cheeks * Musculoskeletal * * Tall, thin build resembling Marfanoid habitus〔 * * Long limbs (dolichostenomelia) * * High-arched feet (pes cavus) * * Knock knees (genu valgum) * * Pectus excavatum and Pectus carinatum * Mental retardation * Seizures * Psychiatric disease * Eye anomalies: * * Ectopia lentis – in contrast to Marfan syndrome which features upward ectopia lentis, downward dislocation is the typical finding of homocystinuria or subluxation of lens * * Myopia (nearsightedness) * * Glaucoma * * Optic atrophy * * Retinal detachment * * Cataracts * Vascular disease * * Extensive atheroma formation at a young age which affects many arteries but not the coronary arteries * * Intravascular thrombosis 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Homocystinuria」の詳細全文を読む スポンサード リンク
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