Thyroid peroxidase gene mutations causing congenital hypothyroidism in three Turkish families.
In Turkey congenital hypothyroidism (CH) occurs with a prevalence of one in 2,736 newborns while the worldwide incidence is one in 3,000-4,000 newborns. 85-90% of these cases are due to dysgenesis of the thyroid gland, whereas defects in thyroid hormone synthesis account for 10-15%. The majority of patients with dyshormonogenesis have a defect in thyroid peroxidase (TPO). To date, more than 60 different mutations have been described in the TPO gene, mostly single nucleotide substitutions. Five children from three consanguineous families were diagnosed with CH on the basis of clinical symptoms and signs--goiter, macroglossia and prolonged jaundice at newborn age. Two different mutations in the TPO gene were identified. Affected children in families I and II had a nonsense mutation in exon 10 (R540X). Genotyping of polymorphic markers within the TPO gene revealed that these families shared a common haplotype, suggesting a founder effect. In the third family, a novel mutation (G319R) in exon 8 was identified.
Ozbek
Mehmet Nuri
MN
Cukurova University, Department of Pediatric Endocrinology and Metabolism, Faculty of Medicine, Balcali, Adana, Turkey.
Uslu
Abdi Burak
AB
Onenli-Mungan
Neslihan
N
Yuksel
Bilgin
B
Pohlenz
Joachim
J
Topaloglu
Ali Kemal
AK
D018389:Codon, Nonsense; D003409:Congenital Hypothyroidism / Q000453:epidemiology / Q000235:genetics*; D004252:DNA Mutational Analysis; D005192:Family Health; D005260:Female; D018703:Founder Effect; D006042:Goiter / Q000209:etiology / Q000235:genetics / Q000473:pathology; D006239:Haplotypes; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007453:Iodide Peroxidase / Q000235:genetics*; D008297:Male; D010375:Pedigree; D020641:Polymorphism, Single Nucleotide; D014421:Turkey / Q000453:epidemiology
D018389:Codon, Nonsense; D007453:Iodide Peroxidase