Abstract:

Objective Toinvestigate the clinical phenotype and molecular genetic characteristics of Maturity⁃ onset diabetes of the youngtype 2（MOYD2），and to explore the correlations between GCK genotype and clinical phenotypes. Methods From April 2011 to October 2021，clinical data of 32 children diagnosed with MODY2 in Department of Endocrinology of Guangzhou Women and Children′s Medical Center were collected. Sanger sequenc⁃ ing and family investigation for GCK gene were conducted. Parents of the children without GCK gene variation were assayed for the whole exon profile and their molecular genetic characteristics were analyzed in depth. Results A total of 32 children（male=19 and female=13）with the onset age ranging from 1⁃day to 18⁃year old were included and the medium value was approximately 8⁃ year old. Fasting blood glucose was slightly elevated in all patients， with mean value of（6.7 ± 0.6）mmol/L，and the mean value of HbA1c was（5.9 ± 0.96%）. All patients didn′t present the symptoms caused by hyperglycemia. The levels of blood glucose in the 31 patients remained stable during the follow⁃up 4 months till 75 months. A total of 30 different heterozygous variants were found in the 32 children， including 5 new variants and 2 spontaneous variants. Conclusions Mild hyperglycemia occurred in children with⁃ MODY2 after birthand there was no significant difference for the clinical phenotypes caused by different GCK gene variations. Children with no family history but highly suggestive of MODY2 should undergo GCK gene sequencing to avoid missed diagnosis，and relevant family members should be screened to aid the optimization of treatment plan. No hot spot variation of GCK gene was found in this study. 

Key words:

genotype, phenotype, glucokinase gene, diabetes