Routine mutation screening of HNF-1α and GCK genes in MODY diagnosis: How effective are the techniques of DHPLC and direct sequencing used in combination?

Abstract

Aims/hypothesis. Mutations in the hepatocyte nuclear factor (HNF)-1α and glucokinase (GCK) genes are the major causes of monogenic forms of Type II (non-insulin-dependent) diabetes mellitus (Maturity-Onset Diabetes of the Young subtypes, MODY). We evaluated the effectiveness of fluorescent single-strand conformation polymorphism (F-SSCP), denaturing high-performance liquid chromatography (DHPLC) and sequencing based mutation detection in the molecular diagnosis of MODY. Our goal is to identify a rapid, efficient and cost effective mutation detection method for the molecular diagnosis of MODY and other human genetic disorders. Methods. We evaluated the accuracy of DHPLC in screening for MODY 2 and 3 mutations. In addition, we compared the sensitivity, specificity, cost, handling time and analysis time of fluorescent single-strand conformation polymorphism, denaturing high-performance liquid chromatography and direct sequencing screening methods. Results. Denaturing high-performance liquid chromatography is a recently developed method for mutation detection. It is cost effective, powerful and reliable and quite suitable for 22 out of the 24 fragments required for MODY 2 and 3 testing. However, exons 1 and 7 of the HNF-1α gene are very polymorphic and so direct sequencing is faster as well as more efficient and reliable. Conclusion/interpretation. Our results suggest that combining denaturing high-performance liquid chromatography and direct sequencing is a good approach for the routine detection of HNF-1α and GCK mutations in MODY families. Denaturing high-performance liquid chromatography appears to be a powerful tool in genetic testing and the method could be applied to the molecular diagnosis of other human genetic diseases.