title: Thyroid hormone resistance detected by routine neonatal screening.
abstract: We report the clinical and laboratory findings, and molecular analysis of a Brazilian patient with resistance to thyroid hormone syndrome (RTH) detected by neonatal screening. The index case was born at term by normal delivery with 2,920 g and 45 cm. TSH of the neonatal screening test performed on the 5(th) day of life was of 13.1 µU/mL (cut-off = 10 µU/mL). In a confirmatory test, serum TSH level was 4.3 µU/mL, total T4 was 19 µg/dL (confirmed in another sample, Total T4 = > 24.0 µg/dL), free T4 was 3.7 ηg/dL, and free T3 was 6.7 pg/mL. Direct sequencing of the beta thyroid hormone receptor gene revealed mutation c.1357C>A (P453T), confirming the diagnosis of RHT. Family study demonstrated the presence of RTH in his 1-year-and-3-month-old sister, in his 35-year-old father, and in his 68-year-old paternal grandfather. All of them had goiter and only his father had received an erroneous diagnosis of hyperthyroidism. The present case shows that clinical evaluation and a judicious interpretation of total T4/free T4 concentrations in a newborn recalled due to slightly altered neonatal TSH can contribute to the diagnosis of RTH.
authors.affiliation: Division of Endocrinology, Department of Clinical Medicine, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, SP, Brazil. lmzmacie@fmrp.usp.br
authors.forename: Léa Maria Zanini
authors.initials: LM
authors.lastname: Maciel
authors.forename: Patrícia Künzle Ribeiro
authors.initials: PK
authors.lastname: Magalhães
mesh_terms: D006801:Humans; D007231:Infant, Newborn; D008297:Male; D009154:Mutation; D015997:Neonatal Screening / Q000592:standards*; D010375:Pedigree; D011988:Receptors, Thyroid Hormone / Q000235:genetics; D018382:Thyroid Hormone Resistance Syndrome / Q000175:diagnosis* / Q000235:genetics; D013963:Thyroid Hormones / Q000097:blood
chemical_list: D011988:Receptors, Thyroid Hormone; D013963:Thyroid Hormones