Congenital hypothyroidism is a condition that affects children from birth. It is caused by a partial or complete loss of thyroid function (hypothyroidism).
The thyroid gland makes hormones that are important for controlling:
- how the body grows
- how the brain develops
- how the body turns food into energy (metabolism)
Congenital hypothyroidism happens when the thyroid gland fails to develop or function properly.
Diagnosis
All newborns are tested for congenital hypothyroidism as part of newborn screening.
Congenital hypothyroidism: heel prick screening
Causes
There are different forms of the condition.
Some babies may have a very small thyroid gland in their neck or no gland at all. Other babies may not be able to make the hormone thyroxine.
Thyroxine is a hormone made by the thyroid gland. It helps a baby’s body grow, develop, and use energy properly. It is especially important for brain development and normal growth.
It is important to know the cause. A scan of the thyroid gland soon after the diagnosis can check this.
About 1 in every 3,500 babies born in Ireland may have the condition. Most cases happen in people with no history of the condition in their family.
Some children with a family history or an atypical form (rare cases) will need genetic testing to find out the cause. In these cases the child often has a thyroid gland, but does not make enough of the thyroid hormone.
Early detection allows early treatment and the prevention of symptoms.
Treatment
If untreated, congenital hypothyroidism can lead to problems with learning and development.
If treatment begins in the first month after birth, babies usually develop normally.
Most children with congenital hypothyroidism need treatment with the hormone thyroxine.
Some children may have their treatment reviewed at around age 2 to 3. A small number of children may be able to stop treatment, but only under medical supervision.
Otherwise treatment is for life. The dose of thyroxine will be changed as the child grows.
The child will usually have check-ups with a paediatrician until they are are fully grown. After that, follow-up care will continue with their GP.