Homocystinuria

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

Signs and tests:

During physical examination of the child, the health care provider may notice dislocation of the lens of the eye and/or myopia. There may be a history of frequent thromboembolic episodes.

Tests:

• A skeletal X-ray shows osteoporosis.
• A standard ophthalmic exam confirms myopia and dislocated lens. Affected children may also have cataracts, glaucoma, and retinal detachment.
• An amino acid screen shows elevated methionine and homocystine levels.
• A liver biopsy and enzyme assay shows an absence of the enzyme cystathionine synthase.
• A skin biopsy with a fibroblast culture shows an absence of cystathionine synthase.