CPS1 and carbamoyl phosphate synthetase I deficiency disease: Patient II‐1 and III‐1 were both diagnosed as carbamoyl phosphate synthetase 1deficiency (CPS1D, MIM #237300) since they both carried compound heterozygous variations in CPS1 gene, which are c.2429A > C/ c.2876A > G (in Patient II‐1) and c.2339G > A/ c.3520C > T (in Patient III‐1), inherited from their parents, respectively.