[Ocular and systemic complications of homocystinuria: a report of five cases].

Homocystinuria is an autosomal recessive disorder of methionine metabolism due to cystathionine B-synthetase deficiency. It is the second most common inborn error of amino acid metabolism after phenylketonuria. In addition to the eyes, the skeletal, central nervous and vascular systems are usually affected by homocystinuria. We report two family cases of two sisters and two brothers with homocystinuria revealed by lenticular dislocation into the anterior chamber, associated with mental and growth retardation, and an isolated case of homocystinuria revealed by poor vision with Marfan syndrome and mental retardation. They all underwent surgical lensectomy with anterior vitrectomy under general anesthesia with anaesthesic precautions to prevent vascular thrombosis. Ocular complications are common in patients with homocystinuria. Treatment must include dietary changes to reduce the incidence of ectopia lentis and mental retardation. Surgical treatment with modern microsurgical techniques should be considered in advanced ocular manifestations of homocystinuria.