Organic Acidaemias

3-Methylcrotonyl CoA Carboxylase Deficiency (3MCC)


3-Methylcrotonyl CoA Carboxylase Deficiency (3MCC) is an inherited autosomal recessive disorder where the body is unable to process certain parts of proteins properly. 3MCC is an organic acid condition because it can lead to harmful amounts of organic acids and toxins in the body.


3MCC is diagnosed during newborn screening via the heel prick test taken 48-72 hours after birth.

Prevalence of 3MCC

1:50,000 estimated worldwide.


3MCC treatment largely involves restricting protein intake to prevent the build-up of 3-hydroxyisovaleric acid and 3 methylcoronlglycine. Many 3-MCC individuals also require supplements of carnitine.

Support Links & Materials

Organic Acidurias Handbook

OA Fruit and Veg Counting Lists

OA General Protein Counting Lists