An unconscious 37-year-old man is brought to the ER. His wife reports that they were at home having dinner celebrating his birthday. She indicates that normally he does not drink but they were having champagne for the celebration. She indicates that shortly after they finished the bottle he became disorientated and irritable and then he began experiencing delusions. When he began to have a seizure she called 911. By the time the ambulance arrived he was unconscious. Blood tests taken when he was admitted show significantly elevated serum ammonia. A deficiency in which of the following enzymes is most likely the cause of this patients symptoms?

Question

Quizplus · Accepted Answer

A deficiency in citrin, which is involved in the urea cycle, can lead to elevated ammonia levels, causing symptoms like disorientation, irritability, delusions, and seizures.  Citrullinemia type II (CTLN2) is caused by deficiency in the gene encoding the mitochondria transporter citrin (SLC25A13). Manifestations of CTLN2 are recurrent hyperammonemia with neuropsychiatric symptoms including nocturnal delirium, aggression, irritability, hyperactivity, delusions, disorientation, restlessness, drowsiness, loss of memory, flapping tremor, convulsive seizures, and coma. The symptoms of CTLN2 are often provoked by alcohol and sugar intake, as well as by certain medications, and/or surgery.

An Unconscious 37-Year-Old Man Is Brought to the ER