Citrin Deficiency (also called Citrullinemia type II)
Citrin is a protein that is needed to transport the amino acid aspartate into the urea cycle. This type of protein is called a transporter. Adults with citrin deficiency (also called citrullinemia type II) can present with hyperammonemia, and cyclical behavior abnormalities including aggression, irritability, and hyperactivity, as well seizures, and coma. Infants and children with citrin deficiency present differently and can have abnormalities of liver and failure to thrive. These patients can also have the dietary peculiarity of avoiding sugars rather than protein (which most urea cycle patients avoid). The majority of patients reported have been Japanese or Asian who share common mutations in the Citrin gene. Citrin deficiency is typically diagnosed by a biochemical analysis and genetic testing.