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Multiple Endocrine Neoplasia Type 1
Familial
multiple endocrine neoplasia type 1 (MEN1) is a disorder of the endocrine glands; these
are glands which make and release hormones into the blood stream. MEN1 is also known as
Wermer's syndrome, after the first doctor to describe it.
MEN1
is a rare condition, occurring in about 3 persons out of 100,000. It affects both sexes
equally and shows no racial, or ethnic preferences.
How
are the endocrine glands affected in MEN1 ?
The
glands involved grow abnormally resulting in small tumours which secrete certain chemical
substances known as ‘hormones’. The parathyroid glands may produce too much parathyroid hormone. The pituitary gland may produce too
much prolactin or growth
hormone. The pancreas may produce
too much insulin or gastrin.
Increased secretion of these hormones produces characteristic syndromes each with its
group of signs and symptoms.
What
effects will this condition have on me ?
The
clinical presentation of MEN1 is very variable. The symptoms you have will depend on which
particular hormone(s) your body is overproducing. This may be one or several in MEN1. For
an outline of the various syndromes of hormone excess follow the individual links for each
condition.
The
majority of patients present with these problems:
1. stomach
ulceration
2. low blood glucose
causing lightheadedness, weakness, blurred vision and sweating.
3. raised blood calcium
which can cause kidney stones
4. pituitary dysfunction -
ie. Headaches, visual symptoms
5. severe diarrhoea
I
feel quite well at the moment - should I wait till I get symptoms ?
Syndromes
of hormonal excess are often asymptomatic for prolonged periods. Patients with MEN1 can
develop symptoms at any age but the condition rarely presents in childhood or after the
age of 60 years. If you are at risk by reason of having an affected family member your
specialist will probably measure your blood calcium , prolactin and gastrin hormone
levels.
No.
These endocrine tumours are usually benign and do not spread to other parts of the body
like cancers do. They may cause local pressure effects e.g. compression of the visual
pathways by pituitary tumours. It is often the case that the tumours producing the excess
hormones are very tiny and may be difficult to find except by using sophisticated imaging techniques. The pancreatic tumours may spread to the liver and
elsewhere in the body causing concern and need for chemotherapy.
I
have MEN1 - Will my children get it as well ?
Your
children have a 50 % chance of inheriting this condition.
All first degree relatives (i.e. immediate family members) should be screened.
What
methods are available for early detection ?
Genetic
screening - the abnormal gene is located on chromosome number 11. You have 46 chromosomes.
If you have the abnormal gene then biochemical testing will be required yearly. Your
children will also be screened for this condition by genetic testing. If the abnormal gene
is not present then your child is safe.
Treatment
depends on the glands affected. Surgical removal of the affected gland is the usual
therapy though drug treatment may be used in certain conditions.
Parathyroid
- surgical removal
prolactinoma -
medical treatment or surgical removal
GH
secreting pituitary adenoma -surgical removal or possibly medical treatment
How
long do I need to continue attending follow up ?
Affected
individuals may develop new facets of the syndrome after many years. As much as twenty years may elapse between the
diagnosis of one condition and the next. For this reason prolonged follow up at a
specialist endocrinologists clinic is
advisable.
Genetic
counselling consists of a discussion between your doctor and yourself/your family with
regard to the implications of screening you family members for the gene responsible for
transmitting this disease. A positive test may have a profound impact on an individuals psychological well being or
‘peace of mind’ and also have implications for life insurance. You may want to
discuss issues relating to having children and the possibility of making a diagnosis in an
unborn child. At the end of this discussion you will be given the opportunity to make an
informed decision on whether you and your family wish to undergo further tests.
Will
I develop all the conditions?
This
is unlikely. 95 out of 100 patients develop the raised calcium 40 out of 100 an
abnormality of the pancreas producing excess gastrin or insulin whereas 30 out of 100
develop a pituitary problem such as prolactin or growth hormone secretion. These do not
develop together but possibly decades apart. Usually the raised calcium occurs first.
What
tests are done during follow up ?
Screening
usually begins at the age of 10-15 years and continues to age 60 y. Some 40% of patients
will show evidence of the disease by age 20 years whereas 80% will present on screening by
age 50 y. It is most unlikely that the condition will occur after the age of 60 years.
Blood
tests to measure levels of the various hormones and calcium will be done usually on an
annual basis. A magnetic resonance (MR) scan of the pituitary gland may also be requested
every 5 years.
I
would like to learn more; Where can I get further information about MEN1?
Links:
www.niddk.nih.gov/health/endo/endo.htm
Patient Support
Website
www.mensociety.com
Ó NHS Tayside; 2006; version 1.0
Disclaimer; no liability whatsoever is accepted for information given and all such information, especially with regard to drug usage (UK version provided), must be checked with a person’s health provider.