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MCADD - heel prick screening


Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is an inherited condition.

People with MCADD are unable to break down fats from their food quickly enough to produce energy in times of illness. This is especially important if they have a fever or diarrhoea, or are vomiting or fasting.

This is because a particular enzyme is either missing or not working properly. This can cause a build-up of toxins and low blood glucose (sugar).

If left untreated, MCADD can cause serious life-threatening complications, such as brain damage, coma or even death.

Babies born in Ireland with MCADD

It's estimated that around 1 in every 66,000 babies born in Ireland has MCADD.

Babies with MCADD inherit one altered gene from each parent.

How the heel prick can help

If the heel prick suggests your baby may have MCADD, they will be referred to a specialist.

If your baby has MCADD, they can have a normal diet, as long as they:

  • frequently take special high energy drinks when they're ill – this includes common illnesses such as fever, diarrhoea, or vomiting
  • avoid long periods without feeding during the newborn period and infancy even when well – the length of time your child can go without eating is known as the maximum "safe fasting time" and it varies depending on age; you'll be given advice about this

If the diagnosis and treatment begins early, your baby can lead a healthy and active life and the potentially life-threatening complications of MCADD can be averted.

On very rare occasions, there is a risk that newborn babies may become very sick and show symptoms of MCADD before they have the heel-prick screen, or before they get the results of the heel-prick screen. Symptoms of MCADD include drowsiness, poor feeding, vomiting, low energy and seizures. If you have any concerns about your newborn baby you should contact your doctor.

page last reviewed: 28/11/2018
next review due: 28/11/2021