small subgroup of people with Type 2 diabetes
develop the disease in their 20s rather than in their
50s or 60s. Most people in this group have a strong
family history of diabetes and are less likely to be
obese than other Type 2 diabetics.
These people, who account for less than five percent
of Type 2 diabetes cases, have maturity onset diabetes
of the young (MODY).
far, scientists have identified five genes that can
put a person at risk for developing MODY, and they are
continuing to look for more. Each of these genes interferes
with the normal release of insulin
by the pancreas. (This is in contrast to Type 1 diabetics,
who fail to produce insulin because the immune system
destroys the insulin-producing cells.) With too little
insulin being produced, cells of the body are unable
to use the sugar glucose for fuel.
there are five genes that cause MODY, only three are
Although this was the first gene discovered, it is
responsible for diabetes in only a small number of
MODY families. A mutation in this gene causes a severe
form of diabetes. In fact, 30 percent of people with
a mutation in HNF-4alpha require insulin to control
This is the most common gene that is mutated in MODY
families, accounting for 50 to 60 percent of MODY
cases. It normally helps regulate how the pancreas
releases insulin in response to glucose. People with
a mutation in GCK develop a relatively mild form of
diabetes that rarely requires insulin for treatment.
Mutations in this gene account for roughly 25 percent
of MODY families. People with a mutation in HNF-1alpha
develop a more serious form of diabetes and are at
high risk for eye disease.
you have a family history of MODY, you might wonder
if there is a genetic test to help
you figure out if you (or other family members) are
at risk. Although most MODY families have a mutation
in one of the identified MODY genes, there is no commercially
available test for MODY. (Some labs will do genetic
testing in MODY families for research purposes).
this time, whether or not you carry a MODY gene the
only way to prevent or delay Type 2 diabetes is to exercise
regularly and maintain a weight that is appropriate
for your height.
Stoffel, M. and Duncan, S. A. (1997). The maturity-onset
diabetes of the young (MODY1) transcription factor HNF4alpha
regulates expression of genes required for glucose transport
and metabolism. Proc Natl Acad Sci USA, 94, 13209-13214.
Velho, G., et al. (1992). Primary pancreatic beta-cell
secretory defect caused by mutations in glucokinase
gene in kindreds of maturity onset diabetes of the young.
Lancet, 340, 444-448.
Yamagata, K., et al. (1996). Mutations in the hepatocyte
nuclear factor-1alpha gene in maturity- onset diabetes
of the young (MODY3) [see comments]. Nature,