Homocystinuria caused by cystathionine beta-synthase deficiency - Mutations resulting in decreased cystathionine beta-synthase activity represent the most common cause of homocystinuria (MIM 236200). Some clinical manifestations of this form of homocystinuria include: myopia, ectopia lentis (downward subluxation), retinal degeneration and detachment, vascular occlusions, osteoporosis, scoliosis, kyphosis, increased long bone length with skeletal disproportions, arachnodactyly, pectus abnormalities, restricted joint mobility and genu valgum. The connective tissue findings overlap to a considerable extent with Marfan syndrome (MFS1; MIM 154700). Central nervous system manifestations can include mental retardation, psychiatric disturbances or seizures. Pancreatitis and fatty changes in the liver have also been noted. Inheritance is autosomal recessive.