engleski

GCK mutations in Croatian MODY patients

Introduction: Maturity onset diabetes of the young (MODY) is clinically and genetically heterogeneous group of diabetes inherited in autosomal dominant manner. It usually occurs in adolescence or young adulthood and accounts for at least 1-3% of all diabetes. GCK-MODY is one of four most common type of MODY with estimated prevalence of 1:1000. It is characterized by mild, stable fasting hyperglycemia which is often discovered incidentally during routine medical screening. Materials and Methods: After clinical examination, 56 patients with stable hyperglycemia, small 2 hour increment in OGTT, positive family history of type 2 or gestational diabetes and negative pancreatic antibodies were tested for GCK-MODY. The promoter, whole coding region and flanking intronic regions of the GCK gene were analyzed by Sanger sequencing. Pathogenicity of identified mutations was verified in reference databases for mutations related with GCK-MODY. Results: 17 different mutations in GCK gene were found in 32 patients. Most of the mutations were in exon 7 (six mutations in 16 patients) and in exon 9 (five mutations in 5 patients). The most common mutation was p.Thr228Met in exon 7 found in 8 patients from 4 different famillies. One patient was apparently homozygous for mutation p.Gly170Asp, but its true homozygosity is not yet confirmed, it can be a result of an allele dropout due to SNP in the primer region. In one patient we detected a novel variant c.806T>G, p.Phe269Cys in exon 7. Conclusions: GCK-MODY is frequently underdiagnosed and inadequately treated. Treatment is rarely necessary if the mild hyperglycemia remains stable.

GCK gene ; diabetes ; Sanger sequencing

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