Homocystinuria (HCU)

Homocystinuria (HCU) is an inherited condition caused by an altered gene. It can cause a build-up of certain amino acids in the blood.

High levels of these amino acids can lead to problems such as:

  • eye problems
  • impaired brain development
  • bone disorders
  • blood clots
  • possible strokes

Babies born in Ireland with HCU

Around 1 in every 69,400 babies born in Ireland has HCU. This is roughly 1 baby every year.

If both parents carry the altered gene they have a 1 in 4 chance of having a baby with HCU.

How heel prick screening can help

Babies with HCU benefit from early diagnosis and treatment.

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

Your baby will then be put on a special diet and medicine. This is a protein-restricted diet with supplements of vitamins, amino acids and minerals. This diet is for life. It will reduce the risk of them developing the problems that HCU can cause.

Milder forms of HCU may not be detected by screening.

Page last reviewed: 12 December 2022
Next review due: 12 December 2025