Homozygous mutation in the insulin receptor gene and mild form of insulin resistance syndrome; a case report

Insulin receptor mutations lead to heterogeneous disorders; as severe as Donohue syndrome or as mild as “type A insulin resistance syndrome”. Patients with severe disorders are homozygous or compound heterozygous mutations. Generally patients with type A insulin resistance syndrome have been found to be heterozygous mutations, homozygous type mutations may rarely be responsible for this disease. We reported a novel homozygous mutation p.Leu260Arg on exon 3 on INSR gene in a patient with type A insulin resistance syndrome. In this article, we report an adolescent with type A insulin resistance syndrome due to a novel homozygous mutation on the INSR gene and detailed her medical follow-up. Different mutations in the INSR gene causes different phenotype and different inheritance pattern also, our report is important to making disease mechanisim understand and also helping genetic counseling process.