New Gene Linked to Maturity-Onset Diabetes of Youth (MODY) Identified: Interview With Diabetologist

Dr. V. Mohan, Chairman & Chief of Diabetology, Dr. Mohan’s
Diabetes Specialities Centre, and ICMR Centre for Advanced Research on
Diabetes, spoke to Medindia about MODY and the new gene
discovery.

Q: What is
the prevalence of patients diagnosed with MODY in India?

Ans: Approximately about 1% – 2%
of all patients with diabetes probably have MODY. However, as genetic
testing needs to be done to diagnose MODY and large-scale
epidemiological studies are extremely difficult to do,
the exact prevalence of MODY remains unknown. However, if we narrow down the
clinical phenotype to those who have diabetes in three or more generations in
the family and follow the other clinical criteria for MODY, then out of every
100 patients in whom we do genetic testing for MODY, about 25 – 30% are found
to have MODY. There are about 14 known forms of MODY,
of which MODY 1 and 3 are the most common types. In India, MODY 3 is the most
common, but we know that the prevalence of MODY 3 is higher among the Western
population.

Q: What are
the genetic tests to diagnose MODY?

Ans: There is a panel of genetic tests to diagnose the different forms
of MODY. If clinically suspected, the test should be done as soon as the
diagnosis of diabetes is made, so that the proper treatment can be administered
from the very beginning. For testing MODY, we use a genetic chip called
the Next Generation Sequencing (NGS),
which helps us to screen the entire genetic mutation. In our
recent breakthrough research, we discovered a new gene mutation called NKX6-1, which is MODY 15 that occurs due to
the mutation in chromosome 17. In patients with MODY,
NKX6-1 were functionally impaired. NGS can determine the type of MODY,
which helps us determine the type of treatment the patient is likely to respond
to.

Q: If a person has a strong
family history of diabetes, at what age should he/she take the genetic test for
MODY?

Ans: We do not recommend a
genetic test for MODY before being diagnosed with diabetes. MODY is more common
among individuals before the age of 25 years. Thus, an individual with a strong
family history of diabetes may have to take a blood sugar test at the age of 15.
If the test is positive, he/she can go for a genetic test to diagnose the type
of MODY. A family might go through a lot of mental trauma, if they were
informed that their child might develop MODY. Thus, it is highly recommended
that the genetic test to be taken only if the individual is
diabetic.

Q: Can technologies
like CRISPR be of any help in treating these genetic conditions?

Ans: CRISPR technology can be used to edit the gene mutations in the human
genome thus helping in correcting and treating these disease conditions. But,
before that, one needs to find the mutation and prove that the particular
mutation is causing the disease. Then it can be edited using CRISPR. These
techniques are not yet applied in the case of MODY and it may not be
useful.

Source: Medindia