Methylmalonic acidemia with homocystinuria Methylmalonic acidemia with homocystinuria type cblF Lysosomal membrane cobalamin transporter deficiency Combined defect in adenosylcobalamin and methylcobalamin synthesis, type cblF orphanet OMIM:277380 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. CblF defect Cobalamin F defect Methylmalonic aciduria with homocystinuria, type cblF ICD10:E72.1