Worth C, Hird B, Tetlow L, et al. - Since scintigraphy can identify congenital hypothyroidism (CH) subtypes classified as dysplasia, the gland in situ (GIS) and ectopia, but is not performed in all centres, researchers retrospectively examined the role of scintigraphy in a single tertiary centre cohort to identify CH subtypes. Between 2007 and 2017, babies who screened positive for CH were studied (n = 418 of 534,783). Three hundred three patients started levothyroxine. Scintigraphy showed three subtypes: GIS (n = 139, 46%) ectopia (n = 84, 28%) and dysplasia (n = 80, 26%). Thyroid scintigraphy differentiates CH subtypes and shows a higher than predicted proportion of patients with GIS and ectopia. In half of those with GIS, CH is permanent.