Disorders of Intracellular Cobalamin Metabolism is related to homocystinuria due to defect in methylation cbl e and hypermethioninemia. An important gene associated with Disorders of Intracellular Cobalamin Metabolism is MMACHC (Metabolism Of Cobalamin Associated C), and among its related pathways/superpathways are Metabolism of water-soluble vitamins and cofactors and Diseases of glycosylation. Affiliated tissues include spinal cord and eye.