MODY diabetes
MODY diabetes
Maturity-onset diabetes of the young (MODY) is the most common type of monogenic diabetes. MODY diabetes can be distinguished to different types by their genetic background. It can be caused by gene variants at least in 11 genes. The most common types (>5% of cases) are MODY1 (HNF4A, hepatic nuclear factor-4 alfa), MODY2 (GCK, glucokinase) and MODY3 (HNF1A, Hepatocyte nuclear factor 1-alpha). The less common types are PDX1 (MODY4), HNF1B (MODY5), NEUROD1 (MODY6), KLF11 (MODY7), CEL (MODY8), PAX4 (MODY9), INS (MODY10) and BLK (MODY11). The most common reason for MODY diabetes in Finnish population are mutations in GCK gene (40% of the MODY cases) or HNF1A gene (40% of the MODY cases).
We recommend genetic testing of the MODY diabetes when family history shows dominantly inherited diabetes which manifests at under the age of 25 year and a clinical picture does not fit to symptoms of type 1 diabetes. Genetic testing of family members is also recommended to those ones who are at risk of inheriting the mutation or to searching for a founder mutation.
Although de novo mutations can arise, wider screening of family members is essential to ensure that those with diabetes have the correct diagnostic /status and those at risk of inheriting the mutation have been tested for diabetes and/or consider to participate predictive genetic testing.
Regions not coveredin thsese genetic tests:
– CEL, RefSeq-transkript NM_001807 exons 1 and 9-11, due to CELP pseudogene and 33 bases long VNTR-repeat (Variable Number of Tandem Repeats) in exon 11.
Coding areas of the genes are sequenced by Sanger or NGS (Next Generation Sequencing) method. Deletion analyses are done by MLPA method.
The analysis is performed from a whole blood sample (EDTA). Instructions for storage and sending the sample as well as prices for DNA screening are given in the request form. The report and interpretation of the results are mailed to the address given in the order 6-8 weeks after the arrival of the blood sample.