Congenital hypothyroidism

Congenital hypothyroidism is defined as deficiency of thyroid hormone from birth (1).

• occurs in about 1 in 4000 live births in the UK
• twice as often in females than in males
• around 85% of cases are sporadic and 15% are hereditary (2)

The development of the central nervous system is intrinsically reliant on thyroxine from early foetal life, and some infants may have developed irreversible brain damage before birth. However, neonatal screening with the commencement of thyroxine therapy within 2 weeks of birth has enabled many infants to attain normal intellectual development.

Infants with primary hypothyroidism have raised TSH and lowered thyroxine.

Reference:

• (1) Rastogi MV, LaFranchi SH. Congenital hypothyroidism. Orphanet J Rare Dis. 2010;5:17
• (2) Association for Clinical Biochemistry (ACB), British Thyroid Association (BTA), British Thyroid Foundation (BTF) 2006. UK guidelines for the use of thyroid function tests