Methylmalonic acidemia is an inherited condition in which the body is unable to process certain proteins and fats properly. Signs and symptoms usually appear in early infancy and vary from mild to life-threatening. Affected infants can experience vomiting, dehydration, weak muscle tone (hypotonia), developmental delay, lethargy, hepatomegaly, and failure to thrive. Long-term complications can include feeding problems, intellectual disability, chronic kidney disease, and pancreatitis. Without treatment, this condition can lead to coma and death in some cases. Mutations in the MUT, MMAA, MMAB, MMADHC, and MCEE genes cause methylmalonic acidemia. It is inherited in an autosomal recessive fashion. Methylmalonic acidemia is treated with a low-protein, high-calorie diet, certain medications, antibiotics and, in some cases, organ transplantation.
The Human Phenotype Ontology (HPO) provides the following list of features that have been reported in people with this condition. Much of the information in the HPO comes from Orphanet, a European rare disease database. If available, the list includes a rough estimate of how common a feature is (its frequency). Frequencies are based on a specific study and may not be representative of all studies. You can use the MedlinePlus Medical Dictionary for definitions of the terms below.
|Signs and Symptoms||Approximate number of patients (when available)|
|Abnormality of the renal tubule||90%|
|Nausea and vomiting||90%|
|Feeding difficulties in infancy||50%|
|Neurological speech impairment||50%|
|Abnormality of neutrophils||7.5%|
|Abnormality of the globus pallidus||-|
|Autosomal recessive inheritance||-|
|Delayed CNS myelination||-|
|Failure to thrive||-|
|Stage 5 chronic kidney disease||-|
Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.
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Nonprofit support and advocacy groups bring together patients, families, medical professionals, and researchers. These groups often raise awareness, provide support, and develop patient-centered information. Many are the driving force behind research for better treatments and possible cures. They can direct people to research, resources, and services. Many groups also have experts who serve as medical advisors. Visit their website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.
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What is the average life expectancy of an individual with methylmalonic aciduria? I understand it is a rare disease and that all cases are different. And how many cases of cobalamin C deficiency are there in the U.S.? See answer