<s>[INST] <<SYS>> This is a medical question of type : frequency <</SYS>> How many people are affected by carbamoyl phosphate synthetase I deficiency ? [/INST] Carbamoyl phosphate synthetase I deficiency is a rare disorder; its overall incidence is unknown. Researchers in Japan have estimated that it occurs in 1 in 800,000 newborns in that country. </s>