[Analysis of novel mutations in the insulin receptor gene of a family with type A insulin resistance syndrome].

This study aimed to identify mutations in the human insulin receptor gene (INSR) and investigate their role in the pathogenesis of severe insulin resistance syndrome. Sanger sequencing of the INSR gene was performed on a patient clinically suspected of having type A insulin resistance syndrome admitted to the Department of Endocrinology, the First Medical Center of Chinese PLA General Hospital. Upon identifying mutations, relevant exons were sequenced in her first-degree relatives. Additionally, control groups consisting of individuals with type 2 diabetes and those with normal glucose tolerance were screened for the mutation detected in the patient. Functional predictions of the INSR protein were made using MutationTaster, SIFT, and PolyPhen2 software. A previously unreported heterozygous missense mutation, c.3652G/A (Asp1218Asn), in exon 20 was identified in both the proband and her father. This mutation was not present in any of the control individuals. Multiple prediction tools indicate that this mutation likely disrupts gene/protein structure or function. The c.3652G/A (Asp1218Asn) heterozygous mutation in INSR is a novel variant that plays a significant role in the pathogenesis of severe insulin resistance in this Chinese family.