Diabetes
MODY
"Maturity
Onset Diabetes of the Young" is a genetic form of
diabetes causing failure of the beta cells, It is
believed to affect up to 5% of all people diagnosed
with both type 1 and type 2 diabetes
What is
MODY diabetes?
Maturity
Onset Diabetes of the Young affects approximately
one or two per cent of people who have diabetes, and
may often go unrecognised in its early stages. It
is a form of diabetes that develops before the patient
reaches 25. It also runs in families, and can pass
from one generation to the next. MODY does not always
require insulin treatment.
Why is
MODY inherited so easily?
MODY is
directly caused by the change in a single gene, and
all children of an affected parent have a 50 per cent
chance of inheriting this gene, and consequently developing
MODY themselves.
Why does
MODY differ from other strains of diabetes, why does
it matter?
Knowing
and understanding MODY and even the different forms
of MODY (six types have been identified), means that
the affected person can be treated in the most appropriate
way possible. Advice can also be provided about how
the disease will progress, and what complications
can be expected. Furthermore, other family members
can be advised about the risks of inheriting the disease.
What are
the different types of MODY?
The most
common MODY type is HNF1 alpha. This is responsible
for 70 per cent of MODY. The amount of insulin produced
by the pancreas becomes less as the person gets older,
and MODY develops during adolescence or the early
twenties. Glucokinase is the second type of MODY,
and occurs when this gene (that aids the body in recognising
blood glucose levels) malfunctions. This type of MODY
can be hard to identify, and symptoms can be particularly
slow in manifesting themselves. It is usually picked
up during routine testing. When a person is pregnant,
it is important to screen for it.
HNF4 -
alpha is a less common form of MODY that is often
diagnosed at a later stage. HNF1 - beta is a type
of MODY associated with renal cysts. PDX1 and IPF1
are the same type of MODY, and are incredibly rare,
affecting only one UK family to date. NeuroD1 is another
rare type of MODY, affecting only two families in
the UK. Little information is available about the
rarer forms of MODY.
What if
You Have MODY?
- MODY
is very like Type 2 diabetes in its effect on your
body. Elevated blood sugars injure you slowly over
many years, causing neuropathy, retinopathy, heart
disease and the other ugly complications of diabetes.
- The
recommended treatment for MODY depends on the severity
of the diabetes. Some people with MODY can maintain
normal blood sugar levels by restricting carbohydrates.
The Glucokinase version of MODY is the one most
amenable to dietary control.
Others, however, may be treated with very low doses
of a sulfonylurea drug or insulin. Doctors assume
you'd prefer a pill to shots, so they often suggest
sulfonylurea drugs rather than insulin. But the
side effects of the sulfonylurea drugs, which include
Amaryl and Glyburide, are significant. They may
cause relentless hunger and weight gain and possibly
raise the risk of heart attack. Sulfonylurea drugs
also tend to cause hypos at doses high enough to
give near-normal blood sugars. In addition, there
is some possibility that using them over time causes
the pancreas beta cells to become exhausted and
burn out. Many people with MODY diabetes find insulin
gives them better control and is less likely to
cause hypos at doses that give tight blood sugar
control. Used in the tiny doses characteristic of
MODY insulin won't usually cause weight gain.
- If you
suspect you have MODY and your doctor wants you
to start insulin or a sulfonylurea drug, be sure
to start at a very low dose. The starting dose of
either a sulfonylurea drug or insulin that is appropriate
for a person who is an insulin resistant Type 2
may be anywhere from two to ten times higher than
the dose that works well for a person with MODY.
So a typical type 2 dose may cause dramatic hypos.
The recommended starting dose for Amaryl for someone
with MODY, for example, was .25 mg, but since this
doesn't adjust for body size, if you are small,
even this dose may be way too much. With insulin,
start with 1 unit and work up to the appropriate
dose. Many people with MODY may do well with as
little as 4-8 units a day.
- If
you suspect you have MODY diabetes and are of childbearing
age, and if there is diabetes in your spouse's family
consider genetic testing. Though it is very rare
to have two copies of the same MODY gene, a child
who inherits two copies of the same MODY gene will
be born with a severe form of diabetes.
What
complications are caused by MODY?
It has
recently been found that MODY can initiate complications.
Managing the disease strictly is just as important
for MODY patients as other types of diabetic.
I am worried
I might have MODY, what should I do?
Seek expert
opinion as soon as possible.
