Development Of A DNA Biochip For Detection Of Known DNA Mutations Associated With MODY2 And MODY3

Objective Maturity-onset diabetes of the young(MODY) is a monogenic form of diabetes mellitus characterized by autosomal dominant inheritance, an early onset of the disease with at least one family member with diabetes diagnosed before the age of 25 yr, and an impairment of pancreaticβ-cell function. Patients with MODY may erroneously be classified as type 2 diabetes (T2DM) due to the unrepresentative early symptom, and MODY may comprise up to 2~5% of T2DM. Presently, mutations in six different genes have been shown to cause MODY1~6. These are genes encoding hepatocyte nuclear factor (HNF)-4α, glucokinase(GCK), HNF-1α, insulin promoter factor-1(IPF-1), HNF-1β, and NeuroD1. Although the true relative prevalence of the six distinct MODY subtypes is unknown and varies substantially in different populations, mutations in the genes encoding GCK(MODY2) and HNF-1α(MODY3) are by far the most prevalent. In our study, we developed an oligonucleotide biochip for synchronous multiplex detection of 13 known DNA mutations associated with MODY2 and MODY3 in Han foreign citizen of Chinese origin.Methods Clinical data and peripheral blood samples were obtained from the 35 objects including 6 affected individuals,their relatives(6 genealogies) and 10 healthy controls.Allele-specific oligonucleotide probes were covalently immobilized on the NHS(n-hydroxy-succinamide) modified glass slides,and then hybridized with Cy5-labled DNA fragments amplified from sample DNAs by a multiplex asymmetric PCR (MAP) method . The 35 objects and 10 healthy controls were investigated using the oligonucleotide biochip and identificated through DNA sequencing.Results The results showed that No.5 genealogy had an IVS6nt+37T→C mutation in the MODY2(GCK) gene,while No.3 genealogy had an IVS2nt-23C→T mutation in the MODY3(HNF-1α) gene.In the healthy controls, none of the 13 related mutations was found.The results of the DNA biochip were consistent with those by DNA sequencing.Conclusions Clearly,the DNA biochip combined with MAP method would become a valuable tool in multiplex detecting of the point mutations in DNA leading to MODY 2 or MODY3 in Han foreign citizen of Chinese origin.Moreover,this biochip format could be modified to extend to the screening scope of another type of MODY and SNPs for any other human single gene mutation diseases.