Liver transplantation for citrullinaemia improves intellectual function

Arginosuccinic acid synthetase (ASA) (EC 6.3.4.5) deficiency (citrullinaemia) (McKusick 215700) is a well-recognized cause of neonatal hyperammonaemic coma with poor long-term intellectual function, despite good medical management.

Cadaveric hepatic transplantation was performed in a 12-year-old boy with citrullinaemia under poor biochemical control. Subsequent development of fulminant hepatic failure necessitated a second cadaveric transplant. Psychometric assessments before and after transplantation were performed using a variety of age-appropriate tests.

Normalization of plasma ammonium in our patient post transplantation has resulted in dramatic improvement in mental functioning and well-being and he now enjoys a normal diet. Psychometric assessment confirmed decline in his abilities prior to transplantation with particular post-transplantation improvement in perceptual organization and visuospatial abilities; these did not, however, return to normal. His family report considerable reduction in stress associated with the unpredictable nature of previous hyperammonaemic crises and recurrent hospitalization.

Liver transplantation should be considered as an early therapeutic option in children with citrullinaemia to prevent ongoing cerebral insult associated with hyperammonaemia.