Incidence
Methylmalonic Acidemia (MMA) is estimated to affect one out of every 50,000 to 100,000 babies born in the United States. MMA is caused by cobalamin disorders A and B is only one form of Methylmalonic Acidemia.
Incidence by ethnicity
It also creates a high number of false-positive results at a ratio of 5 infants without the disorder to 1 infant with the disorder. While the birth prevalence for specific disorders is known to vary among different racial/ethnic groups, identifying a higher number of MMA false-positive cases with Hispanic ethnicity was unexpected.
Incidence by gender
C3 levels are generally higher in males (except for Blacks), the overall MMA false-positive rate is not significantly higher for males (53.5% male, 95% CI 49.1–57.9%). This may reflect an inherently higher C3/C2 in females, likely due to lower C2.
Incidence by age
C3 levels are generally higher in males (except for Blacks), the overall MMA false-positive rate was not significantly higher for males (53.5% male, 95% CI 49.1–57.9%). This may reflect an inherently higher C3/C2 in females, likely due to lower C2.
Information on disease
Methylmalonic Acidemia (MMA), an inborn metabolic disorder associated with intermittent and often severe metabolic decompensation.
Cause
MMA is an inherited condition in which the body is unable to break down certain fats and proteins. It is considered an organic acid condition because it can lead to a harmful amount of organic acids and toxins in the body. MMA caused by cobalamin A or cobalamin B deficiencies is one type of Methylmalonic Acidemia. Children with this form of the condition have trouble producing cobalamin enzymes A and B. Cobalamin enzymes are necessary for the body to break down certain foods.
Signs and symptoms
The signs of Methylmalonic Acidemia cobalamin A and B disorders (Cbl A, B) can begin at any time from birth to adulthood. In most cases, signs first appear during infancy (as early as the first few days after birth).
For babies, signs of Cbl A, B can include
- Sleeping longer or more often
- Vomiting
- Weak muscle tone (also called hypotonia)
- Fever
- Breathing trouble
- Increased number of illnesses and infections
- Increased bleeding and bruising
Many of these signs may occur when your baby eats foods that their body cannot break down. They can be triggered by long periods of time without eating, illnesses, and infections.
Testing and follow-up
It comes off in medical language as C3/C2.
Outlook
Babies may not survive their first episode of symptoms from this disease.
The screening
Although screening using tandem mass spectrometry (MS/MS) now identifies most newborns with MMA is detected with Newborn Screening (NBS) by elevated propionylcarnitine (C3) and its ratio with Acetylcarnitine (C3/C2).
Confirmation
Avoiding false-positive results in NBS could reduce the emotional and financial burden of follow-up testing. Tests that may be done to diagnose this condition include:
- Ammonia test
- Blood gases
- Complete blood count
- CT scan or MRI of the brain
- Electrolyte levels
- Genetic testing
- Methylmalonic acid blood test
- Plasma amino acid test
Treatment
There are two types of methylmalonic acidemia (MMA): cobalamin disorders and MUT deficiencies. One of the ways these two types of MMA differ is their response to vitamin B-12. MUT deficiencies are considered non-vitamin B-12 responsive.
Supplements
Cobalamin deficiencies are vitamin B-12 responsive. In these cases, vitamin B-12 injections can prevent symptoms. This type of treatment is more successful for Cobalamin A disorders than for Cobalamin B disorders, but it is helpful for both.
Your baby’s doctor might also recommend L-Carnitine supplements. These supplements help the body break down fats and they can remove harmful substances from the body. Your baby’s doctor will need to write a prescription for these supplements.
Medicines
Antibiotics can also help to reduce MMA levels.
Dietary Treatment
Your baby will need a very carefully monitored diet. Children with MMA need to avoid certain fats and proteins because their bodies cannot break down these substances. Your baby’s doctor can recommend special formulas made for babies with organic acid conditions. These formulas will likely need to be continued through adulthood.
Therapies
Liver or kidney transplantation (or both) have been shown to help some patients. These transplants provide the body with new cells that help breakdown Methylmalonic acid normally.
Referrences
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