Homocystinuria Presenting as Ectopia Lentis and Thrombotic Manifestations in Two Siblings: A Case Series

Homocystinuria (HCU) is an autosomal recessive metabolic disorder due to a defect in cystathionine beta synthase activity which results in homocysteine accumulation in the body. We report a case series of two siblings,11-year-old girl and 3-year-old boy, studied retrospectively. They were born to a nonconsanguineous parents and diagnosed as a case of HCU based on the presence of ectopia lentis and development of cerebral venous thrombosis and infarction. Child who presented late with paresis had delayed developmental milestones with low intelligence quotient (IQ), while the second child diagnosed at a younger age had relatively normal IQ and cognitive development. Serious clinical sequelae such as life-threatening thromboembolic events at a young age and mental retardation can be prevented by early screening and prompt treatment of the patients detected to have HCU.