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Pectus excavatum

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Homocystinuria

Alternative Names: Cystathionine beta synthase deficiency Symptoms: A family history of homocystinuria Nearsightedness Flush across the cheeks Tall, thin build Long limbs High-arched feet (pes cavus) Knock-knees (genu valgum) Pectus excavatum Pectus carinatum Mental retardation Psychiatric disease Signs and tests: During a physical examination of the child, the health care provider may notice a tall, thin (Marfanoid) stature with pectus deformity of the chest or scoliosis. If there is poor or double vision, an ophthalmologist should perform a dilated eye exam where dislocation of the lens of the eye or nearsightedness may be observed. Text Continues Below There may be a history of frequent blood clots. Mental retardation, slightly low IQ, or psychiatric disease are common. Tests: A skeletal X-ray shows osteoporosis. A standard ophthalmic exam confirms nearsightedness and a dislocated lens. Affected children may also have cataracts, glaucoma, and retinal detachment. An amino acid screen of blood and urine shows elevated methionine and homocysteine levels. A liver biopsy and enzyme assay shows an absence of the enzyme cystathionine beta synthase. A skin biopsy with a fibroblast culture shows an absence of cystathionine beta synthase. Genetic testing may show a mutation in the cystathionine beta synthase gene.

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