New diagnostic tool for rare diabetics form could cut insulin dependence

TNN Dec 13, 2013, 07.30AM IST
CHENNAI: Around 5% of those with diabetes who are on insulin may not have to take recourse to the needle anymore, with a new genetic diagnostic method on the block.
A month after Christian Medical College, Vellore, announced new insights into the diagnosis of a less recognised problem in diabetes — Maturity-Onset Diabetes of the Young (Mody) — doctors at Madras Diabetes Research Foundation have gone a step further by introducing tests that would detect defective genes that cause the disorder.
"Mody is a non-insulin dependent Type-2 diabetes, which usually occurs below 25 years of age. Since Type 1 diabetes also occurs for those below 25 years, many patients with Mody are wrongly diagnosed and unnecessarily put on insulin for life," said Dr V Mohan of the foundation on Thursday to launch the genetic tests at his centre.
According to diabetologists, Mody, an inherited form of diabetes, make up as much as 5% of presumed type 1 and type 2 diabetes cases in a large population. They say using next generation DNA sequencing technology, 13 genes that are responsible for causing different types of Mody can be found.
"In the traditional method, we had to send patients for different tests to identify each of the13 genetic defects that are found to cause Mody. With this new technology, all the tests can by done together," said Dr R M Anjana, joint managing director of Mohan's Diabetes Centre.
"It is important to differentiate types of diabetes as treatment methods differ. Patients found to have Mody 1 and 3 need to take only oral tablets and there is no need for insulin. Some patients with Mody 2 may not even need medical treatment if they learn to manage their diet and exercise," she said.
Unlike other forms of diabetes, Mody is not related to obesity and, in some forms, the blood sugar problems are so mild that is escapes diagnosis. "This makes genetic testing even more important for this form of diabetes. It won't just help the patient, but it will prompt screening of relatives and helps identify other cases in the family," she said.
The new technology also works out cheaper than the tradition method. Studying three genes cost around Rs 50,000 and at least 35 to 40 days per patient. But using the new technology, they can study 13 genes at the rate of eight patients a week. While CMC is doing the test for 10 genes free of cost, the test at Mohan's Diabetes Centre will cost between Rs 10,000 and 15,000.
Doctors say the new technology could change the course of treatment for a person with diabetes. "Since it is cheaper we are able to conduct more tests and as a result we are discovering rare forms of Mody. Recently, we detected four cases of Mody 6. Across the world, there is published research of only five cases. There are so many more waiting to be discovered," said Dr Nihal Thomas, professor and head, department of endocrinology, diabetes and metabolism, CMC. In India, there are around 70 million people with diabetes.