Rare hereditary metabolic disease with peripheral neuropathy Methylmalonic acidemia with homocystinuria Methylmalonic acidemia with homocystinuria, type cblC Cobalamin C defect Combined defect in adenosylcobalamin and methylcobalamin synthesis, type cblC ICD10:E72.1 CblC defect OMIM:277400 orphanet type methylmalonic acidemia with homocystinuria is a form of methylmalonic acidemia with homocystinuria (see this term), an inborn error of vitamin B12 (cobalamin) metabolism characterized by megaloblastic anemia, lethargy, failure to thrive, developmental delay, intellectual deficit and seizures. Methylmalonic aciduria with homocystinuria, type cblC Metabolic disease with pigmentary retinitis