 MCADD
The government has announced plans for all newborn babies in England
to be checked for a rare inherited condition.
The test will be performed as part of the heel prick test, which is routinely
performed in the first two weeks of life. Read on to find out more about
this rare but potentially fatal disease
What is MCADD?
MCADD stands for Medium Chain Acyl-CoA Dehydrogenase Deficiency and is
pronounced 'emcad'. It is a rare hereditary disease caused by a faulty
gene which is unknowingly passed down through generations. If two carriers
of the faulty gene have a baby together, they can pass the defective gene
to their child.
People with MCADD cannot fast for very long. Fasting occurs when your
body has used up all the food you have eaten and begins to break down
fat into energy for the body. People with MCADD have problems breaking
down fat into energy, so the body begins to fail once the food has run
out.
Bopping Bumps
Fats in your food, and those stored in your body, are broken down into
energy by an enzyme called medium chain acyl-CoA dehydrogenase (MCAD).
Some people are either missing this enzyme or it isn't working properly.
Normally, if you miss a meal or while you're sleeping, your body draws
energy from fat stores. People with MCADD cannot do this and their blood
sugar can fall dangerously low, leading to a build-up of chemicals in
their blood.
How many babies are affected?
- Between 1 in 10,000 and 1 in 15,000 babies are estimated to be born
in the UK each year.
- It is predominantly a disorder found in white, northern Caucasian
people.
- If both parents carry the faulty gene, a baby has a 50 per cent chance
of being a carrier, a 25 per cent chance of having the disease, and
a 25 per cent chance of having neither.
What are the signs and symptoms?
Children with MCADD often show effects for the first time between 3 months
and 2 years of age, and these come in bouts of illness known as metabolic
crises. Some early signs of a crisis include;
- Irritability
- Extreme sleepiness
- Loss of appetite
- Changes in behaviour
- Sometimes fever, diarrhoea and vomiting
If left untreated, further symptoms may include
- Low blood sugar
- Breathing problems
- Seizures
- Coma
- Death
It is thought that 1 in 100 deaths from Sudden Infant Death Syndrome
(SIDS) is caused by undiagnosed MCADD.
What are the long term effects?
People with MCADD are usually healthy when they are not having a metabolic
crisis. However, 25 per cent of sufferers die when they have their first
crisis, and this rises to 50 per cent if the first crisis occurs after
the age of 2 years. For sufferers who survive, one third will sustain
significant neurological damage.
Repeated crises can cause permanent brain damage resulting in learning
difficulties. However, people with MCADD who are treated usually lead
normal, healthy lives.
How is it treated?
MCADD is usually treated by avoiding long periods of fasting.
- Avoid going without food - Regular feeds are needed to prevent low
blood sugars. This may involve having a starchy snack before bedtime
and waking for snacks during the night. Babies and young children should
not go longer than 4-6 hours without food. Teens and adults can usually
go up to 12 hours without food if they are well.
- Diet - A high carbohydrate diet can provide many beneficial types
of energy that can be used by the body before reaching the stage where
fats are required to be broken down. Dieticians can advise on the best
diet for your child.
- Illness - Medical treatment should be sought at the first sign of
any illness which can affect appetite, such as a cold, flu or stomach
bug. High glucose drinks should be on hand to prevent a drop in blood
sugar when a child is not eating
How will it be screened?
All newborn babies are currently screened for conditions such as sickle
cell through a 'heel prick' test in the first two weeks of life. This
test involves taking a few drops of blood from your baby's heel. The blood
is then sent to a lab for testing.
Over the next two years, labs will begin testing this blood sample for
MCADD. Your baby will not need an extra heel prick test as enough blood
is already collected. It is thought that the test will pick up 28 new
cases each year which would have otherwise gone undetected.
This will allow for early treatment, so preventing life-threatening crises.
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