Homocystinuria

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Homocystinuria Diagnosis & 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.

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.