Congenital Hypothyroidism
A condition in infancy or early childhood due to an in-utero deficiency of THYROID HORMONES that can be caused by genetic or environmental factors, such as thyroid dysgenesis or HYPOTHYROIDISM in infants of mothers treated with THIOURACIL during pregnancy. Endemic cretinism is the result of iodine deficiency. Clinical symptoms include severe MENTAL RETARDATION, impaired skeletal development, short stature, and MYXEDEMA.
Hypothyroidism
A syndrome that results from abnormally low secretion of THYROID HORMONES from the THYROID GLAND, leading to a decrease in BASAL METABOLIC RATE. In its most severe form, there is accumulation of MUCOPOLYSACCHARIDES in the SKIN and EDEMA, known as MYXEDEMA.
Thyroid Dysgenesis
Defective development of the THYROID GLAND. This concept includes thyroid agenesis (aplasia), hypoplasia, or an ectopic gland. Clinical signs usually are those of CONGENITAL HYPOTHYROIDISM.
Neonatal Screening
The identification of selected parameters in newborn infants by various tests, examinations, or other procedures. Screening may be performed by clinical or laboratory measures. A screening test is designed to sort out healthy neonates (INFANT, NEWBORN) from those not well, but the screening test is not intended as a diagnostic device, rather instead as epidemiologic.
Thyroxine
The major hormone derived from the thyroid gland. Thyroxine is synthesized via the iodination of tyrosines (MONOIODOTYROSINE) and the coupling of iodotyrosines (DIIODOTYROSINE) in the THYROGLOBULIN. Thyroxine is released from thyroglobulin by proteolysis and secreted into the blood. Thyroxine is peripherally deiodinated to form TRIIODOTHYRONINE which exerts a broad spectrum of stimulatory effects on cell metabolism.
Thyrotropin
A glycoprotein hormone secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Thyrotropin stimulates THYROID GLAND by increasing the iodide transport, synthesis and release of thyroid hormones (THYROXINE and TRIIODOTHYRONINE). Thyrotropin consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the pituitary glycoprotein hormones (TSH; LUTEINIZING HORMONE and FSH), but the beta subunit is unique and confers its biological specificity.
Thyroid Function Tests
Blood tests used to evaluate the functioning of the thyroid gland.
Thyroid Gland
A highly vascularized endocrine gland consisting of two lobes joined by a thin band of tissue with one lobe on each side of the TRACHEA. It secretes THYROID HORMONES from the follicular cells and CALCITONIN from the parafollicular cells thereby regulating METABOLISM and CALCIUM level in blood, respectively.
Thyroid Hormones
Goiter
Enlargement of the THYROID GLAND that may increase from about 20 grams to hundreds of grams in human adults. Goiter is observed in individuals with normal thyroid function (euthyroidism), thyroid deficiency (HYPOTHYROIDISM), or hormone overproduction (HYPERTHYROIDISM). Goiter may be congenital or acquired, sporadic or endemic (GOITER, ENDEMIC).
Thyroglobulin
Thyroglobulin is a glycoprotein synthesized and secreted by thyroid follicular cells, serving as a precursor for the production of thyroid hormones T3 and T4, and its measurement in blood serves as a tumor marker for thyroid cancer surveillance.
Triiodothyronine
A T3 thyroid hormone normally synthesized and secreted by the thyroid gland in much smaller quantities than thyroxine (T4). Most T3 is derived from peripheral monodeiodination of T4 at the 5' position of the outer ring of the iodothyronine nucleus. The hormone finally delivered and used by the tissues is mainly T3.
Thyroid (USP)
A dehydrated extract of thyroid glands from domesticated animals. After the removal of fat and connective tissue, the extract is dried or lyophilized to yield a yellowish to buff-colored amorphous powder containing 0.17-0.23% of iodine.
Iodide Peroxidase
A hemeprotein that catalyzes the oxidation of the iodide radical to iodine with the subsequent iodination of many organic compounds, particularly proteins. EC 1.11.1.8.
Iodine
Insurance Carriers
Sodium Pertechnetate Tc 99m
Receptors, Thyrotropin
Cell surface proteins that bind pituitary THYROTROPIN (also named thyroid stimulating hormone or TSH) and trigger intracellular changes of the target cells. TSH receptors are present in the nervous system and on target cells in the thyroid gland. Autoantibodies to TSH receptors are implicated in thyroid diseases such as GRAVES DISEASE and Hashimoto disease (THYROIDITIS, AUTOIMMUNE).
Cranial Fontanelles
Phenylketonurias
A group of autosomal recessive disorders marked by a deficiency of the hepatic enzyme PHENYLALANINE HYDROXYLASE or less frequently by reduced activity of DIHYDROPTERIDINE REDUCTASE (i.e., atypical phenylketonuria). Classical phenylketonuria is caused by a severe deficiency of phenylalanine hydroxylase and presents in infancy with developmental delay; SEIZURES; skin HYPOPIGMENTATION; ECZEMA; and demyelination in the central nervous system. (From Adams et al., Principles of Neurology, 6th ed, p952).
Thyroxine-Binding Proteins
Blood proteins that bind to THYROID HORMONES such as THYROXINE and transport them throughout the circulatory system.
Methimazole
A thioureylene antithyroid agent that inhibits the formation of thyroid hormones by interfering with the incorporation of iodine into tyrosyl residues of thyroglobulin. This is done by interfering with the oxidation of iodide ion and iodotyrosyl groups through inhibition of the peroxidase enzyme.
Iodides
Inorganic binary compounds of iodine or the I- ion.
Natal Teeth
Predeciduous teeth present at birth. They may be well formed and normal or may represent hornified epithelial structures without roots. They are found on the gingivae over the crest of the ridge and arise from accessory buds of the dental lamina ahead of the deciduous buds or from buds of the accessory dental lamina. (From Jablonski, Dictionary of Dentistry, 1992)
Macroglossia
The presence of an excessively large tongue, which may be congenital or may develop as a result of a tumor or edema due to obstruction of lymphatic vessels, or it may occur in association with hyperpituitarism or acromegaly. It also may be associated with malocclusion because of pressure of the tongue on the teeth. (From Jablonski, Dictionary of Dentistry, 1992)
Fluoroimmunoassay
Hyperthyroidism
Hypersecretion of THYROID HORMONES from the THYROID GLAND. Elevated levels of thyroid hormones increase BASAL METABOLIC RATE.