Ocular Complications Of Homocystinuria: A Case Report

Homocystinuria is an autosomal recessive disorder of methionine metabolism due to cystathionine B-synthetase deficiency.Its incidence varies between 1/60 000 and 1/250 000 births. Ocular complications are the most constant and most often inaugural. Systemic complications are mainly orthopedic and neurological. The high risk of vascular thrombosis is the main threat to the vital prognosis, hence the interest of prenatal diagnosis by enzymatic determination of cystathionine beta-synthetase on amniocyte and chorionic villus cultures .

We report a case of homocystinuria discovered following ocular complications

ophthalmology B department , Speciality Hospital, Ibn Sina,Rabat, Morroco

M.A., a 10-year-old boy with a history of first-degree consanguinity with mental and psychomotor acquisitions delay, was admitted to the emergency room with scleromalacia of the left eye and bilateral anterior lens dislocation complicated by acute hypertonia.  Clinical examination revealed a typical appearance of a homocystinuric child with mental and staturo-ponderal retardation, malar flush, and thin, graying hair. After biological confirmation of homocystinuria and preparation for anesthesia, a reintegration of the herniated uveal tissue in the left eye was performed as well as a phakophagy and a bilateral anterior vitrectomy with aphakic glasses postoperatively.

Lens ectopia is the most frequent anomaly found in homocystinuria;it's bilateral and inferior in the majority of cases,it may be complicated by posterior or anterior dislocation;other ophtalmic complications: microspherophakia;degenerative lesions of the retinal periphery can lead to retinal detachment;ocular hypertonia may be acute,secondary to pupillary block or anterior lens dislocation;It can become chronic. Anterior staphyloma in these patients is secondary to scleral fragility and hypertonia.Other clinical manifestations can also be found:neurological(mental and psychomotor acquisitions delay),skeletal(marfanoid aspect,osteoporosis...)and vascular:The main threats to the vital prognosis are arterial or venous thrombotic accidents

Through this observation, we recall that homocystinuria is frequently accompanied by ophthalmologic manifestations. The delay in consultation, often due to the associated mental retardation, can jeopardize the functional prognosis of the patients, hence the interest of an early detection and a regular multidisciplinary follow-up.