End organ resistance to thyroid hormone has been described for a number of years: the defect may be partial or generalized. A case of partial end organ resistance to thyroid hormone in congenital hypothyroidism is described, with evidence of an alteration in TSH threshold to feedback inhibition by thyroid hormone. The implications of this factor in the management of hypothyroidism are discussed.

Congenital hypothyroidism, with an estimated incidence of 1 in 5-10 000 births, is probably the commonest endocrine disorder of early childhood. Its importance lies in the devastating effect which it can have on brain development, leading to subnormality and other manifestations such as clumsiness and hyperactivity. It is common experience that the condition is difficult or impossible to recogn...

Pseudohypoparathyroidism (PHP) is a group of disorders characterized by end-organ resistance to the parathyroid hormone (PTH). PHP type 1A includes multihormone resistance syndrome, Albright's hereditary osteodystrophy, and obesity and is caused by mutations in GNAS exon 1 through 13. PHP type 1B (PHP1B), caused by epigenetic changes in the GNAS locus, was initially described as an isolated res...

A pilot screening programme for congenital hypothyroidism covering most of North London, Essex, Bedfordshire, and Hertfordshire entailed carrying out an assay of thyroid-stimulating hormone on single Guthrie dried blood spots. During one year 87 444 babies were screened and 26 cases of primary congenital hypothyroidism detected, giving an incidence of 1:3363. Only two cases (7.7%) had already b...

We describe two cases of fetal goiter in women with no history of thyroid disease. Diagnosis of fetal goiter during antenatal care was made by ultrasound and MRI. Congenital hypothyroidism was confirmed by fetal blood sampling that was treated with weekly intra-amniotic injections of L-thyroxin. One fetus was initially treated with four weekly intra-amniotic injections of 200 μgms of L-thyroxin...

Cord blood thyrotropin (TSH) screening for congenital primary hypothyroidism has been in effect on the island of St. Lucia for the past three years. Umbilical cord blood samples are obtained on Guthrie filter paper and then transported 3,000 miles to Loyola University of Chicago and delivered to the Illinois State Metabolic Screening Laboratory. There TSH is measured by radioimmunoassay (RIA). ...

Genetic defects resulting in deficiency of thyroid hormone synthesis can be found in about 10% of the patients with permanent congenital hypothyroidism, but the identification of genetic abnormalities in association with the transient form of the disease is extremely rare. We report the case of a boy with transient neonatal hypothyroidism that was undiagnosed in the neonatal screening, associat...

National screening for congenital hypothyroidism was established in the United Kingdom in 1982. During 1982-4, 488 infants with primary congenital hypothyroidism were detected by the 25 regional screening laboratories in England, Wales, and Northern Ireland. In addition, one infant had signs of cretinism at birth and was investigated before the screening test was done and four infants were know...

Congenital hypothyroidism (CH) represents one of the most common preventable causes of mental retardation. The fetal hypothalamic-pituitary-thyroid axis begins to function by midgestation and is mature in the term infant at delivery. If fetal hypothyroidism develops, untoward effects may be demonstrated in certain organ systems, including the central nervous system and skeleton. However, most i...

The diagnosis on the basis of low serum thyroxine level wiJh high thyrotropin level of congenital pri1111lfY hypothyroidism in newborn screening programs fails to distinguish between transient hypothyroidism and ectopic thyroid, athyrosis, dyshormonogenesis, or transient hyperthyrotropinemill. The correct use of neonotol thyroid scintigraphy aids in making a specific anatomic diagnosis. We scan...