Introduction

Thyroid disorders occur more frequently in all age groups of people with Down syndrome (DS) than in the general population. The incidence of hypothyroidism in childhood is 5.5%–10% but higher in the first year of life.1 Hyperthyroidism is also more common, particularly in later childhood. Untreated thyroid disorders can cause significant preventable secondary neurodevelopmental impairment and other health issues. Many of the symptoms associated with hypothyroidism can be present in people with DS normally, such as constipation, dry skin, developmental delay and obesity. This means it is difficult to pick up the diagnosis of hypothyroidism clinically in people with DS.

The Down Syndrome Medical Interest Group (DSMIG) published this guideline in April 2020. It should be used alongside the NICE thyroid disorder guideline (NG145). The DSMIG …