Congenital hypothyroidism is the most common neonatal metabolic disorder and results in severe neurodevelopmental impairment and infertility if untreated. Congenital hypothyroidism is usually sporadic but up to 2% of thyroid dysgenesis is familial, and congenital hypothyroidism caused by organification defects is often recessively inherited. The candidate genes associated with this genetically ...

random monoallelic expression. Thus, the hypothesis of non-Mendelian inheritance remains valid, and the search for other mechanisms ensues. They do not exclude a complex situation in which both Mendelian and non-Mendelian mechanisms are at play. In the clinical part of this special issue, thyroid disorders associated with well-known genetic syndromes are carefully analyzed and reviewed. First, ...

The thyroid gland is the first endocrine gland to start developing in the embryo. Morphological and structural developmental anomalies of the thyroid gland are relatively rare. Thyroid developmental anomalies (TDA) (excluding biochemical abnormalities) can be divided into three groups namely agenesis (or athyreosis), dysgenesis, and anomalies due to persistence of the thyroglossal tract (Jain a...

OBJECTIVE To evaluate the etiology of primary congenital hypothyroidism (PCH) identified in the Newborn Screening Program from the state of Santa Catarina, Brazil, from July 2007 to June 2009 in the first visit. SUBJECTS AND METHODS A prospective study was performed in 45 patients with PCH. For the etiological diagnosis, history, physical examination, and additional tests (TSH, free thyroxine...

Background: Thyroid dysgenesis is the most frequent cause of congenital hypothyroidism (CH), and its genetic basis is largely unknown. Hitherto, two mutations in the human thyroid transcription factor 2 (TTF-2) gene have been described in unrelated cases of CH with cleft palate, spiky hair, variable choanal atresia, and complete thyroid agenesis. Here, we describe a novel TTF-2 mutation in a fe...

INTRODUCTION Congenital hypothyroidism (CH) is the most frequent endocrine-metabolic disease in infancy, with an incidence of about 1/2000-4000 newborns (1,2). With the exception of rare cases due to hypothalamic or pituitary defects, CH is characterized by elevated TSH in response to reduced thyroid hormone levels. In absence of an adequate treatment, CH determines growth retardation, delays i...

Thyroid imaging is indicated to evaluate congenital hypothyroidism during newborn screening or in cases of a palpable thyroid mass in children and adolescents. This pictorial essay reviews the ultrasonography (US) of thyroid diseases in children and adolescents, including normal thyroid gland development, imaging features of congenital thyroid disorders (dysgenesis, [aplasia, ectopy, hypoplasia...

NKX2-5 is a homeodomain-containing transcription factor implied in both heart and thyroid development. Numerous mutations in NKX2-5 have been reported in individuals with congenital heart disease (CHD), but recently a select few have been associated with thyroid dysgenesis, among which the p.A119S variation. We sequenced NKX2-5 in 303 sporadic CHD patients and 38 families with at least two indi...