Argininosuccinate Lyase Deficiency is an inborn error of metabolism that affects the urea cycle and induces hyperammonemia in infants and it s catastrophic to development of the nervous system , and most patients even those who are early diagnosed suffer from moderate to severe mental retardation. the good news is Donor cell engraftment with expression of enzyme activity is the goal of liver cell transplantation for inborn errors of liver metabolism with a view to achieving sustained metabolic control. there are few studies made on this subject and one of these patient who receive this treatment was a 3 years old who was shifted from having a sever illness to moderate or late onset disease which is milder , and was able to go to school later on so there is always hope. I recommend referring to one of these centers to assess her case and make a decision about her I hope this helps