Homocystinuria and ectopia lentis.

Homocystinuria is a genetically determined error of metabolism of the amino acid, methionine, which results in increased levels of homocystine and methionine in the blood and urine. A variety of clinical manifestations may result, one of these being the dislocation of the crystalline lens(es). A patient presented in the residency clinic with bilateral ectopia lentis and upon subsequent consultation with her family physician, a diagnosis of homocystinuria was made. This paper discusses the ocular and systemic manifestations of homocystinuria, the differential diagnosis of ectopia lentis, and the management of the systemic disease and its ocular sequelae.