A high prevalence of consanguineous and severe congenital hypothyroidism in an Iranian population

Journal of Pediatric Endocrinology & Metabolism

Volume 9 - Number

Article Type: ---- Unspecified ----

To determine the incidence of permanent congenital hypothyroidism (CH) in Tehran and Damavand, cord blood spots were collected from February 1998-August 2002 and infants with TSH greater than or equal to20 mU/l were recalled. CH was confirmed in neonates (aged greater than or equal to7 days) with serum TSH >10 mU/l and T-4 <84 nmol/l. Cases were followed up until September 2003. Dysgenesis was detected by thyroid imaging. In eutopic cases, serum TSH and T-4 measurements following levothyroxine discontinuation (2-3 years of age) confirmed dyshormonogenesis and transient CH. Of 35,067 neonates, 373 (1.06%) were recalled and 25 (1:1,403 births) had permanent CH (six had transient CH and four remain unknown). Dysgenesis was detected in 18 (1:1,948 births) and dyshormonogenesis in seven (1:5,010 births) infants. Parental consanguinity was present in 10 (55.6%) dysgenetic, three (42.9%) dyshormonogenetic, and overall 6,648 (28.6%) of 23,227 screened infants. Odds ratio (95%CIOR) of consanguinity in permanent CH and dysgenesis was 2.75 (1.17-6.47) and 3.74 (1.33-10.52), respectively. The high prevalence of parental consanguinity in infants with permanent CH warrants genetic assessment.