Classic homocystinuria: clinical, biochemical and radiological observations, and therapeutic outcome of 24 Saudi patients.

We considered the clinical, biochemical and radiological findings, and response to pyridoxine (vitamin B6) of 24 classic homocystinuric patients (15 females, 9 males) diagnosed at King Faisal Specialist Hospital and Research Centre. Common clinical findings included ectopia lentis (20 patients), skeletal system involvement (18 patients), vascular system involvement (9 patients) and mental retardation (all patients to varying degrees). A number of unusual findings were reported. The parents of 21 patients were first-degree relatives and 19 patients had at least one other family member affected by the same disease. Only 4 patients responded to pyridoxine; their methionine level decreased to almost normal range.