Familial homocystinuria.

Two cases of siblings diagnosed as cases of familial homocystinuria are reported. Both the cases have classical presentation of familial homocystinuria including history of dislocation of lens of the right eye. Brother had history of psychomotor retardation while sister had a significant history of deep vein thrombosis. Levels of plasma homocysteine were elevated and urinary homocysteine was positive in both the cases.