The study was carried out was based on a comprehensive genomic analysis of 289 individuals from India which included 152 clinically diagnosed MODY cases and 137 NGT subjects
A study on Maturity Onset Diabetes of the Young (MODY) was published in BMC Medical Genetics journal by Dr V Mohan, Director, MDRF and Dr Radha Venkatesan, Head of Genomics, Madras Diabetes Research Foundation (MDRF), Chennai, in collaboration with Dr Andrew S Peterson, Dr Somasekar Seshagiri and Dr Thong T Nguyen from Genentech, California, and Dr Ramprasad and Sam Santhosh, Chairman, MedGenome, India.
The usual forms of diabetes are type II diabetes, (which comprises 90 – 95 per cent of all forms of diabetes) and type I diabetes. Type II diabetes normally affects adults, and does not require insulin for control of hyperglycemia except in the more advanced stages. Type I diabetes, usually affects children and in this type of diabetes there is complete insulin deficiency and hence they require lifelong insulin injections, several times a day. However, there are many other forms of diabetes which are increasingly being recognised nowadays.
There is a genetic form of diabetes due to a single gene defect and hence these are called as monogenic diabetes. The commonest form of monogenic diabetes is Maturity Onset Diabetes of the Young (MODY) which like type I diabetes also affects young people or children. Patients with MODY are usually lean and because of their young age, they are often wrongly labeled as having type I diabetes and advised to have lifelong insulin injections. MODY can only be diagnosed by doing genetic testing. Further, it is now known that there are 14 different forms of MODY, each with its own unique clinical characteristics. While there have been a few scattered studies on different forms of MODY in India, this was the most comprehensive and largest study of all forms of MODY done in India.
The study was carried out was based on a comprehensive genomic analysis of 289 individuals from India which included 152 clinically diagnosed MODY cases and 137 normal glucose tolerance subjects (NGT). None of the NGT subjects showed any genetic variants associated with MODY. Among the 152 clinically diagnosed MODY subjects, MODY 3 was found to be the commonest MODY which is in keeping with studies in Europe and UK. However, surprisingly, the second commonest MODY detected in India was MODY 12, (ABCC8 MODY). Moreover, 13 of the 14 known forms of MODY were detected in Indians. However, of great interest was the discovery of a novel MODY gene, the NKX6-1 gene which was found to be associated with MODY. Functional assessment of the NKX6-1 variant showed that they were functionally impaired, confirming that they were indeed the cause of MODY’
Dr Mohan said, “The significance of diagnosing monogenic forms of diabetes like MODY is that unless a correct diagnosis is made, patients can be wrongly diagnosed to have type 1 diabetes and advised to have unnecessary lifelong insulin injections. Once the diagnosis of MODY is confirmed, in most forms of MODY, insulin injections can be completely stopped and these patients can be treated with a very inexpensive sulphonylurea tablet which has been used for decades, for treating diabetes. This is a dramatic change as far as the treatment and the life of these patients and their families are concerned.”
Dr Venkatesan adds, “This is the first time in the world, the NKX6-1 gene mutation has been described as a novel form of MODY. Further studies have to be done to see whether this MODY form is unique to Indians or it is present in other ethnic groups as well.”
Santhosh said, “MedGenome is proud to be part of this study. The study will help in further diagnostics research in this domain. The role of genomics in the healthcare industry is poised to grow at an exponential rate, and we endeavor to build a legacy of enabling Precision Medicine in India”.