Apollo Hospitals, Navi Mumbai successfully treated a rare case of Citrullinaemia by performing a liver transplant

Citrullinaemia is a rare autosomal recessive genetic disorder affecting about 1 in 57,000 people worldwide including a neonatal acute form and a late-onset form. Citrullinaemia is caused by deficiency or absence of the enzyme argininosuccinatesynthetase (ASS), one of six enzymes that play a key role in the removal of nitrogen from the body in the process known as the urea cycle. The lack of this enzyme results in excessive accumulation of nitrogen in the form of ammonia in the blood. The symptoms of citrullinemia are seen usually following a protein meal.

The patient, a 7-year-old male was diagnosed with Citrullenaemia at birth by genetic testing. He was the 4^th child in the family. The previous two of the siblings died in the 1^st week of their life and two of the siblings were diagnosed with high ammonia levels, a condition known as citrullinaemia. The patient was managed with medications and dietary restrictions. However, he had multiple episodes of convulsions due to high ammonia levels. Also because of his hyperactivity and behavioural problems, managing him in the growing age was becoming difficult for the family. The family consulted the doctors at Apollo Institutes of Liver disease and Transplantation at Navi Mumbai and were advised liver transplantation to correct the enzyme deficiency, which was the cause of citrullinaemia.

His mother, a 37-year-old female decided to donate her liver. She was heterozygotic carrier of the disease. She donated the left lateral segment of her liver (about 25% of her liver). Immediately after transplantation the patient was put up on intravenous medications to keep his ammonia levels low till the new liver showed good synthetic function. His liver functions tests normalized within a week and ammonia levels decreased without medication.

The treatment of citrullinaemia is aimed at preventing excessive ammonia from being formed or for removing excessive ammonia during a hyperammonaemic episode. Medications that assist in the removal of nitrogen from the body by providing an alternative means of waste nitrogen removal are employed.

Dietary restrictions are aimed at limiting the amount of protein intake to avoid the development of excess ammonia. However, enough protein must be taken in, by an affected infant to ensure proper growth. As argininosuccinatesynthetase enzyme is present in liver, liver transplantation corrects the enzyme deficiency and improves quality of life.