Thyroid status in a large cohort of patients with mental retardation: the TOP-R (Thyroid Origin of Psychomotor Retardation) study.

Objective: Abnormalities in thyroid state may affect development and function of the brain and result in mental retardation (MR). Thyroid parameters have not been systematically investigated in institutionalized MR subjects. The objective is to measure thyroid parameters in a novel cohort of 946 institutionalized subjects.