Synonyms: Combined defect in adenosylcobalamin and methylcobalamin synthesis | Methylmalonic aciduria with homocystinuria
A rare inborn error of vitamin B12 (cobalamin) metabolism characterized by megaloblastic anemia lethargy failure to thrive developmental delay intellectual deficit and seizures. There are four complementation classes of cobalamin defects (cblC cblD cblF and cblJ) that are responsible for methylmalonic acidemia – homocystinuria (methylmalonic acidemia – homocystinuria cblC cblD cblF and cblJ).
Data from Orphanet are used to provide information on a disease's name, synonym(s), and overview. Reference: Access aggregated data from Orphanet at Orphadata. Orphadata: Free access data from Orphanet. © INSERM 1999. Available on http://www.orphadata.org. Data version April 2026
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Methylmalonic acidemia with homocystinuria?
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Advocacy Organizations
Canadian PKU and Allied Disorders (CanPKU)
“To improve the lives of people living with PKU and other inherited metabolic disorders by supporting education, advocacy, access to care, and community connection.”
HCU network america
HCU Network America strives to inform and provide resources for patients and families, create connections, influence state and federal policy, and support the advancement of diagnosis and treatment for HCU and related disorders.
Louisiana Metabolic Disorders Coalition
We support, educate, and advocate for patients & families affected by metabolic disorders.
Mississippi Metabolics Foundation
Our mission at Mississippi Metabolics Foundation (MMF) is to advocate, educate, and support families in MS affected by genetic metabolic disorders/inborn errors of metabolism (IEM's). MMF promotes initiatives and further advancements in legislation, education, research, clinical trials, studies, therapies, targeted treatments, and eventual cures for IEM’s and all rare diseases.
Organic Acidemia Association
We are a 501c3 non-profit organization made up of parents of children with organic acidemia metabolic disorders. Organic Acidemias are a group of inheritable genetic metabolic disorders in which there is a defect in protein metabolism where an essential enzyme is absent or malfunctioning. Our mission is to empower families and health care professionals with knowledge in these disorders. We suppor
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Clinical Trials
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