Methylmalonic acidemia with homocystinuria
Last updated 16 May 2023
Meets Patient’s editorial guidelines
- DownloadDownload
- Share
- Language
- Discussion
- Audio Version
- Add to preferred sources on Google
Methylmalonic acidemia with homocystinuria is a disorder in which the body is unable to correctly process certain protein building blocks (amino acids), fat building blocks (fatty acids), and cholesterol. The body is also unable to convert the amino acid homocysteine to another amino acid, methionine. Individuals with this disorder have a combination of features from two separate conditions, methylmalonic acidemia and homocystinuria. There are several forms of this combined condition, and the different forms have different genetic causes and signs and symptoms. The most common and best understood form, called cblC type (or cobalamin C disease), occurs in about 80 percent of affected individuals.
Description
Methylmalonic acidemia with homocystinuria is a disorder in which the body is unable to correctly process certain protein building blocks (amino acids), fat building blocks (fatty acids), and cholesterol. The body is also unable to convert the amino acid homocysteine to another amino acid, methionine. Individuals with this disorder have a combination of features from two separate conditions, methylmalonic acidemia and homocystinuria. There are several forms of this combined condition, and the different forms have different genetic causes and signs and symptoms. The most common and best understood form, called cblC type (or cobalamin C disease), occurs in about 80 percent of affected individuals.
The signs and symptoms of methylmalonic acidemia with homocystinuria usually develop in infancy, although they can begin at any age. When the condition begins early in life, affected individuals typically grow more slowly than expected. This sign is sometimes iedentified before the baby is born. These infants can also have difficulty feeding and have an abnormally pale appearance (pallor). Eye abnormalities and neurological problems, including weak muscle tone (hypotonia) and seizures, are also common in people with methylmalonic acidemia with homocystinuria. Many infants and children with this condition have delayed development and intellectual disability, and some have an unusually small head size (microcephaly).
Some people with methylmalonic acidemia with homocystinuria develop a blood disorder called megaloblastic anaemia. Megaloblastic anaemia occurs when a person has a low number of red blood cells (anaemia), and the remaining red blood cells are larger than normal (megaloblastic). The signs and symptoms of early-onset methylmalonic acidemia with homocystinuria worsen over time, and the condition can be life-threatening if it is not treated.
When methylmalonic acidemia with homocystinuria begins in adolescence or adulthood, it may change an affected person's behaviour and personality; the person may become less social and may experience hallucinations, delirium, and psychosis. In addition, these individuals can begin to lose previously acquired mental and physical abilities, resulting in a decline in school or work performance, difficulty controlling movements, memory problems, speech difficulties, a decline in intellectual function (dementia), or an extreme lack of energy (lethargy). Some people with methylmalonic acidemia with homocystinuria whose signs and symptoms begin later in life develop a condition called subacute combined degeneration of the spinal cord, which leads to numbness and weakness in the lower limbs, difficulty walking, and frequent falls.
Inheritance patterns
The source lists the following possible inheritance patterns: X-linked recessive; Autosomal recessive. More than one pattern can apply in different cases.
Related genes
Other names
Methylmalonic acidemia and homocystinemia
Methylmalonic acidemia and homocystinuria
Methylmalonic aciduria and homocystinuria
Vitamin B12 metabolic defect with combined deficiency of methylmalonyl-coA mutase and homocysteine:methyltetrahydrofolate methyltransferase
Vitamin B12 metabolic defect with combined deficiency of methylmalonyl-coA mutase and methionine synthase activities
Related patient information and medicines
Patient information leaflet
Newborn bloodspot test
Mothers of all newborn babies are offered testing for certain rare but serious health conditions by testing blood taken from the baby's heel. This is the blood spot screening programme and it is also known as the heel prick test. Also, a sudden and severe drop in blood sugar levels can occur. All four devolved nations of the United Kingdom now.
Patient information leaflet
Diabetic kidney disease
Diabetic kidney disease is a complication that occurs in some people with diabetes. It can progress to kidney failure in some cases. Treatment aims to prevent or delay the progression of the disease. Also, it aims to reduce the risk of developing cardiovascular diseases such as heart attack and stroke which are much more common than average in.
Patient information leaflet
Macrocytosis and macrocytic anaemia
Macrocytosis refers to red blood cells which are larger than normal. It does no... Tests of your liver function. Checks to rule out conditions which people with some types of macrocytic anaemia develop, such as diabetes, underactive thyroid gland, and homocystinuria (a condition in which a chemical called homocysteine and related substances build.
Patient information leaflet
Diabetes and illness
If you have diabetes - or have to care for someone who has - it's important to be prepared to cope with illness. Don't delay in contacting your doctor or nurse if you need advice or support. If you're still not able to keep any fluids down get medical hel... There is also further information in the following sections on Type 1 diabetes and Type 2.
Patient information leaflet
Diabetic neuropathy
Diabetic neuropathy is a type of nerve damage that can occur if you have diabetes. Diabetic neuropathy is a common complication of both type 1 diabetes and type 2 diabetes. The best way to prevent or treat diabetic neuropathy is to keep your blood sugar (glucose) and blood pressure well controlled, to attend regular diabetes checks and to avoid.
Patient information leaflet
Diabetes and high blood pressure
It is important to keep your blood pressure under control if you have diabetes. Stroke, heart disease and other complications are more likely if your blood pressure is high. Tackling unhealthy factors in your lifestyle can help. Some people need medication if lifestyle changes aren't enough. Keeping your blood pressure well controlled is important.
Further reading and references
- Methylmalonic acidemia with homocystinuria; MedlinePlus, National Library of Medicine.
- Chern T, Achilleos A, Tong X, Hill MC, Saltzman AB, Reineke LC, Chaudhury A, Dasgupta SK, Redhead Y, Watkins D, Neilson JR, Thiagarajan P, Green JBA, Malovannaya A, Martin JF, Rosenblatt DS, Poche RA. Mutations in Hcfc1 and Ronin result in an inborn error of cobalamin metabolism and ribosomopathy. Nat Commun. 2022 Jan 10;13(1):134. doi: 10.1038/s41467-021-27759-7.
- Coelho D, Kim JC, Miousse IR, Fung S, du Moulin M, Buers I, Suormala T, Burda P, Frapolli M, Stucki M, Nurnberg P, Thiele H, Robenek H, Hohne W, Longo N, Pasquali M, Mengel E, Watkins D, Shoubridge EA, Majewski J, Rosenblatt DS, Fowler B, Rutsch F, Baumgartner MR. Mutations in ABCD4 cause a new inborn error of vitamin B12 metabolism. Nat Genet. 2012 Oct;44(10):1152-5. doi: 10.1038/ng.2386. Epub 2012 Aug 26.
- Coelho D, Suormala T, Stucki M, Lerner-Ellis JP, Rosenblatt DS, Newbold RF, Baumgartner MR, Fowler B. Gene identification for the cblD defect of vitamin B12 metabolism. N Engl J Med. 2008 Apr 3;358(14):1454-64. doi: 10.1056/NEJMoa072200.
- Froese DS, Fowler B, Baumgartner MR. Vitamin B12 , folate, and the methionine remethylation cycle-biochemistry, pathways, and regulation. J Inherit Metab Dis. 2019 Jul;42(4):673-685. doi: 10.1002/jimd.12009. Epub 2019 Jan 28.
- Gueant JL, Chery C, Oussalah A, Nadaf J, Coelho D, Josse T, Flayac J, Robert A, Koscinski I, Gastin I, Filhine-Tresarrieu P, Pupavac M, Brebner A, Watkins D, Pastinen T, Montpetit A, Hariri F, Tregouet D, Raby BA, Chung WK, Morange PE, Froese DS, Baumgartner MR, Benoist JF, Ficicioglu C, Marchand V, Motorin Y, Bonnemains C, Feillet F, Majewski J, Rosenblatt DS. APRDX1 mutant allele causes a MMACHC secondary epimutation in cblC patients. Nat Commun. 2018 Jan 4;9(1):67. doi: 10.1038/s41467-017-02306-5.
- Huemer M, Baumgartner MR. The clinical presentation of cobalamin-related disorders: From acquired deficiencies to inborn errors of absorption and intracellular pathways. J Inherit Metab Dis. 2019 Jul;42(4):686-705. doi: 10.1002/jimd.12012. Epub 2019 Feb 13.
- Krautler B. Biochemistry of B12-cofactors in human metabolism. Subcell Biochem. 2012;56:323-46. doi: 10.1007/978-94-007-2199-9_17.
- Lerner-Ellis JP, Tirone JC, Pawelek PD, Dore C, Atkinson JL, Watkins D, Morel CF, Fujiwara TM, Moras E, Hosack AR, Dunbar GV, Antonicka H, Forgetta V, Dobson CM, Leclerc D, Gravel RA, Shoubridge EA, Coulton JW, Lepage P, Rommens JM, Morgan K, Rosenblatt DS. Identification of the gene responsible for methylmalonic aciduria and homocystinuria, cblC type. Nat Genet. 2006 Jan;38(1):93-100. doi: 10.1038/ng1683. Epub 2005 Nov 27.
- Pupavac M, Watkins D, Petrella F, Fahiminiya S, Janer A, Cheung W, Gingras AC, Pastinen T, Muenzer J, Majewski J, Shoubridge EA, Rosenblatt DS. Inborn Error of Cobalamin Metabolism Associated with the Intracellular Accumulation of Transcobalamin-Bound Cobalamin and Mutations in ZNF143, Which Codes for a Transcriptional Activator. Hum Mutat. 2016 Sep;37(9):976-82. doi: 10.1002/humu.23037. Epub 2016 Jul 12.
- Quintana AM, Yu HC, Brebner A, Pupavac M, Geiger EA, Watson A, Castro VL, Cheung W, Chen SH, Watkins D, Pastinen T, Skovby F, Appel B, Rosenblatt DS, Shaikh TH. Mutations in THAP11 cause an inborn error of cobalamin metabolism and developmental abnormalities. Hum Mol Genet. 2017 Aug 1;26(15):2838-2849. doi: 10.1093/hmg/ddx157.
- Rutsch F, Gailus S, Suormala T, Fowler B. LMBRD1: the gene for the cblF defect of vitamin B(1)(2) metabolism. J Inherit Metab Dis. 2011 Feb;34(1):121-6. doi: 10.1007/s10545-010-9083-9. Epub 2010 May 6.
- Sloan JL, Carrillo N, Adams D, Venditti CP. Disorders of Intracellular Cobalamin Metabolism. 2008 Feb 25 [updated 2021 Dec 16]. In: Adam MP, Bick S, Mirzaa GM, Wallace SE, Amemiya A, editors. GeneReviews(R) [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2026. Available from http://www.ncbi.nlm.nih.gov/books/NBK1328/
- Yu HC, Sloan JL, Scharer G, Brebner A, Quintana AM, Achilly NP, Manoli I, Coughlin CR 2nd, Geiger EA, Schneck U, Watkins D, Suormala T, Van Hove JL, Fowler B, Baumgartner MR, Rosenblatt DS, Venditti CP, Shaikh TH. An X-linked cobalamin disorder caused by mutations in transcriptional coregulator HCFC1. Am J Hum Genet. 2013 Sep 5;93(3):506-14. doi: 10.1016/j.ajhg.2013.07.022.
Join the conversation
Share your thoughts or experiences with others in our patient communities.
Ask, share, connect.
Browse discussions, ask questions, and share experiences across hundreds of health topics.
Sign up to the Patient newsletter
Your weekly dose of clear, trustworthy health advice - written to help you feel informed, confident and in control.
By subscribing you accept our Privacy Policy. You can unsubscribe at any time. We never sell your data.