Scanning and analysis of the KATP channel mutations in 12 cases of infancy onset type 1 diabetes mellitus

Abstract

Objective To screen the mutation of KATP channel mutations in Chinese pedigrees with infantile onset type 1 diabetes mellitus(T1DM) and neonatal diabetes mellitus. Methods A cohort of 12 children of infant onset T1DM and neonatal diabetes mellitus admitted into Beijing Children's Hospital between March 2004 and June 2013 were selected.PCR amplification and direct sequencing were used to analyze the 39 exons of ABCC8 gene and one exon of KCNJ11.And the mutational sites of the parents of the probands was sequenced in order to identify the inheritance. Results Analysis revealed ABCC8 mutation in 25%(3/12 cases) of the patients, a case of transient neonatal diabetes(TNDM), a case of permanent neonatal diabetes mellitus(PNDM) and a case of infant onset T1DM.All positive patients showed a known heterozygosis mutation in the ABCC8 gene(R1182Q, c.3545G>A, D209E, c.627C>G, E208K c. 622G>A). The residue R1182Q, which was located at a position involved in joining transmembrane domain 2 to nucleotide binding domain 2, the mutations E208K and D209E were located in the intracellular region that links the transmembrane domain with the gatekeeper module.All the three mutations were located throughout the cytoplasm part of SUR1 protein.The TNDM successfully transferred from insulin to oral sulfonylureas therapy. Conclusions There is a complex genetic pathogenesis in neonatal and infant-onset diabetes.The KATP channel activating mutations is one of the main causes of neonatal diabetes mellitus and may cause T1DM in infants in China.Oral Glibenclamide therapy seems highly effective for some patients with the KATP channel activating mutations. Key words: KATP channel; Infancy onset type 1 diabetes mellitus; Neonatal diabetes mellitus; Glibenclamide