Multinodular goiter (MNG) is a common disorder characterized by a nodular enlargement of the thyroid gland. As opposed to toxic MNG, the non-toxic subtype does not result from an inflammatory or neoplastic process. Genetic defects may play a major role in the pathogenesis of familial non-toxic MNG. Some loci have been linked to familial MNG. Germline mutations in DICER1 have been identified as the cause of familial MNG with or without ovarian Sertoli-Leydig cell tumor. DICER1, a member of the RNaseIII family, is involved in the generation of microRNAs, that modulate gene expression at the posttranscriptional level.
