Absence of mutations in PAX8, NKX2.5, and TSH receptor genes in patients with thyroid dysgenesis.
OBJECTIVE
To precisely classify the various forms of TD, and then to screen for mutations in transcription factor genes active in thyroid development.


METHODS
Patients underwent ultrasound, thyroid scan, and serum thyroglobulin measurement to accurately diagnose the form of TD. DNA was extracted from peripheral leukocytes. The PAX8, and NKX2.5 genes were evaluated in all patients, and TSH receptor (TSHR) gene in those with hypoplasia.


RESULTS
In 27 nonconsanguineous patients with TD, 13 were diagnosed with ectopia, 11 with hypoplasia, and 3 with athyreosis. No mutations were detected in any of the genes studied.


CONCLUSIONS
Sporadic cases of TD are likely to be caused by epigenetic factors, rather than mutations in thyroid transcription factors or genes involved in thyroid development.
Unidade de Tireoide, Laboratório de Endocrinologia Celular e Molecular (LIM-25), Disciplina de Endocrinologia, Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo (HCFMUSP), São Paulo, SP, Brazil.
Ester S
ES
Brust
Cristine B
CB
Beltrao
Maria C
MC
Chammas
Tomoco
T
Watanabe
Marcelo T
MT
Sapienza
Suemi
S
Marui
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003409:Congenital Hypothyroidism / Q000235:genetics*; D005260:Female; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D008297:Male; D009154:Mutation; D000072636:PAX8 Transcription Factor; D051761:Paired Box Transcription Factors / Q000235:genetics*; D050033:Thyroid Dysgenesis / Q000175:diagnosis / Q000235:genetics*; D013972:Thyrotropin / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*; D055815:Young Adult
D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins; C095552:NKX2-5 protein, human; D000072636:PAX8 Transcription Factor; C083325:PAX8 protein, human; D051761:Paired Box Transcription Factors; D014157:Transcription Factors; D013972:Thyrotropin