CPS1 and hyperinsulinemic hypoglycemia, familial, 4: In summary, the variant effect and structural predictions of CPS1 Asn674Ile variant, together with the evidence from the case report of the mild CPS1 deficiency seen in a patient with this variant (Kurokawa et al., 2007), suggested that CPS1 Asn674Ile would be a mild pathogenic variant.