Citrin deficiency presents in a number of syndromes, one of which affects adolescents and adults. This is termed Citrullinemia Type II (CTLN2).


Chromosome location: 7q21.3

Gene affected: SLC25A13

Protein: calcium-binding mitochondrial carrier protein Aralar2

Function: liver-type aspartate-glutamate carrier isoform 2 (AGC2)

Deficiency affects aerobic glycolysis, gluconeogenesis, urea cycle, protein synthesis, nucleotide synthesis


Inheritance: autosomal recessive


Clinical features:

(1) sudden onset >= 11 years of age

(2) neuropsychiatric symptoms

(2a) aggression, irritability, restlessness, hyperactivity

(2b) nocturnal delirium, delusions, disorientation, memory loss, personality change

(2c) seizures, flapping tremor

(3) preference for a diet low in carbohydrate (aversion for sugar)

(4) thin habitus resembling anorexia nervosa

(5) hepatic steatosis

(6) variable pancreatitis


Laboratory findings:

(1) recurrent hyperammonemia

(2) hyperlipidema


Episodes may be triggered by:

(1) medications

(2) alcohol

(3) physiologic stress such as surgery

(4) sugar or carbohydrate intake



(1) cirrhosis with hepatoma (hepatocellular carcinoma)

(2) cerebral edema

(3) altered mental status (drowsiness, coma)


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