Citrin deficiency (CD), also known as citrullinaemia type 2, is an inherited metabolic disorder in which the body is unable to make citrin, a protein that helps move substances within the cells.

Citrin helps to break down sugar (carbohydrates), make proteins and nucleotides, and get rid of toxins (ammonia) in the body. It is also important for the liver to work properly.

Individuals with CD often prefer high protein and high fat foods, rather than high carbohydrate foods.

How common is CD?

It is estimated that one in 10,000 to 38,000 people are born with CD. It can occur in both genders, and across all races.