Endocrine Abstracts

Congenital thyroid stimulating hormone (TSH) deficiency occurs due to hypothalamic or pituitary pathology, with consequent impaired stimulation of the thyroid gland by TSH resulting in central congenital hypothyroidism (CCH). Although assumed to be rare, CCH may be more common than previously appreciated with an incidence of up to 1:21 000 reported in the Netherlands. TSH deficiency is most frequently associated with additional pituitary hormone deficits but may also occur in ...

Disorders of thyroid hormone action are classified broadly, to encompass conditions with defective cellular uptake, metabolism or nuclear action of thyroid hormones. Genomic thyroid hormone action is mediated via receptor subtypes (TRalpha, TRbeta) with differing tissue distributions. TRbeta-mediated Resistance to Thyroid Hormone (RTH) is characterised by elevated thyroid hormones, raised metabolic rate and cardiac hyperthyroidism but hepatic resistance (dyslipidaemia, steatos...

Congenital Hypothyroidism (CH) is the commonest inborn endocrine disorder (prevalence 1 in 3000), and occurs either due to failure of normal gland development (thyroid dysgenesis), or due to defective thyroid hormone synthesis in a structurally normal gland (dyshormonogenesis). Mutations in known thyroid transcription factors, and in genes encoding components of the thyroid hormone biosynthetic machinery, have been implicated in CH, attesting to the role of these genes in huma...

Selenocysteine insertion sequence-binding protein 2 (SECISBP2) mediates translational incorporation of selenocysteine into 25 known human selenoproteins, including iodothyronine deiodinases. Two unrelated male subjects, aged 36 years (P1) and 3.6 years (P2), exhibited markedly elevated free thyroxine (fT4), normal/low free triiodothyronine (fT3), but normal thyrotropin (TSH) levels, indicating reduced T4 to T3 conversion:<table b...

Background: Elevated TSH concentration should be assessed and treated with caution because of the possibility of transient thyroid dysfunction, or, in rare cases, measurement interference. We describe a case with a rare cause of elevated TSH level in a 39-year-old mother and her four children.Case Summary: A 39-year-old lady was referred with a long history of high serum TSH ranging between 18.9 to 38.7 (reference interval 0.4-4.0 mU/l) with FT4 concentr...

Introduction: Congenital hypothyroidism (CH) occurs 1 in 3,000-4,000 live-births. The causes of CH can be divided into two groups: thyroid developmental defects (thyroid dysgenesis) and inborn errors of thyroid hormone biosynthesis (dyshormonogenesis). Although mutations in paired box gene 8 (PAX8) usually cause thyroid dysgenesis, they have been reported in association with eutopic thyroid gland without function. PAX8 has been described to have a role in regulating the expres...

Case history: A clinically euthyroid 7-year-old boy was noted to have a persistently elevated TSH 7.35–14 mU/l (NR 0.27–4.2) and normal FT4 15.0 pmol/l (NR 10-24) with negative anti-thyroid peroxidase antibodies. Thyroid ultrasonography revealed a eutopically-located thyroid gland of normal size. Following commencement of levothyroxine, he developed insomnia, irritability and headaches, resulting in cessation of treatment. Growth and development proceeded ...

Neonatal screening for congenital hypothyroidism (CH) in the Republic of Macedonia was piloted in 2002 and implemented nationally in 2007, demonstrating a CH incidence of 1 in 1916. 52.7% cases exhibit a normally-located gland-in-situ (GIS CH), however, although this may indicate genetically-mediated dyshormonogenesis, genetic stratification has not previously been undertaken. We selected singleton GIS CH cases (n=22), born at term, with birth weight >3000 g in wh...

Introduction: Biallelic mutations in the TSHB gene are a recognized cause of isolated congenital central hypothyroidism (CH), with autosomal recessive inheritance. In countries where neonatal CH screening relies on detection of an elevated TSH, such cases are missed, with the potential for delayed diagnosis and subsequent developmental impairment.Case: A female infant presented aged 8 weeks with prolonged jaundice, poor weight gain, constipation...

Background: 21-Hydroxylase deficiency due to mutations in CYP21A2 represents the commonest form of congenital adrenal hyperplasia (CAH). Dyshormonogenetic congenital hypothyroidism (CH) may be due to TPO, TG, DUOX2, DUOXA2, IYD, SLC5A5 and SLC26A4 mutations.Case report: Two of six children born to unrelated parents presented in the neonatal period with salt-losing CAH due to compound heterozygosity in CYP21A2 (maternal...