This is an article written by Brian Chicoine in Success Stories in Developmental Disabilities. Vol II. edited by Dale Antanitus and published in 1993.
Hypothyroidism is seen more frequently in Down Syndrome (DS) than in the general population. Dry skin, constipation, impaired intellect, obesity, hearing impairment, lethargy and depression are manifestations of hypothyroidism. They can also be manifestations of DS or associated health problems. Therefore, it can be difficult to determine if an adult with DS has hypothyroidism using clinical findings alone.
Source: Brian Chicoine, MD