High prevalence of AZFb microdeletion in Iranian patients with idiopathic non-obstructive azoospermia.

Background & objectives: Genetic factors contribute about 10 per cent of male infertility. Among these, genes in azoospermia factor (AZF) region including AZFa, AZFb, AZFc and AZFd on the long arm of Y chromosome are considered most important for spermatogenesis. Deletions in these regions are thought to be involved in some cases of male infertility associated with azoospermia or oligozoospermia. We studied the incidence of AZF deletions among Iranian infertile men with idiopathic non-obstructive azoospermia. Methods: A total of 100 Iranian azoospermic infertile men were selected for the molecular study of Y chromosome microdeletions. The presence of 13 sequence tagged site (STS) markers from AZF region was investigated using multiplex polymerase chain reaction (M-PCR). One hundred fertile men were also studied as control group. Results: Twelve (12%) patients showed Y chromosome microdeletions and among these, deletion in AZFb region was the most frequent (66.67%) followed by AZFc (41.67%), AZFd (33.33%) and AZFa (8.33%), respectively. Interpretation & conclusions: Because of relatively high incidence of Y chromosome microdeletions among Iranian azoospermic patients, molecular screening may be advised to infertile men before using assisted reproductive treatments.

Mutations in the gene encoding paired box domain (PAX8) are not a frequent cause of congenital hypothyroidism (CH) in Iranian patients with thyroid dysgenesis / As mutações no gene PAX8 não constituem uma causa frequente de hipotireoidismo congênito em pacientes iranianos com disgenesia tiroidiana

OBJECTIVE: Congenital hypothyroidism (CH) may be caused by defects in the thyroid or in one of the stages in the synthesis of thyroid hormones. Thyroid dysgenesis may be associated with mutation in the paired box transcription factor 8 (PAX8) gene. We attempted to screen PAX8 gene mutation in 50 CH patients with thyroid dysgenesis. SUBJECTS AND METHODS: The patients were classified in two groups as agenesis and ectopic based on biochemical and para clinical tests. By employing PCR, Single Strand Conformation Polymorphism (SSCP) and sequencing, exons 3 to 12 of PAX8 gene with their exon-intron boundaries were studied. RESULTS: No mutation was found in these patients in any of the exons. CONCLUSION: Our results, once again, indicate that the PAX8 mutation rate is very low and can only explain a minority of the cases. Therefore, it is highly needed to further investigate the genes controlling development and function of thyroid.

OBJETIVO: O hipotireoidismo congênito (HC) pode ser causado por defeitos na formação da tireoide ou em uma das etapas da síntese dos hormônios tireoidianos. A disgenesia da tireoide pode ser associada a mutações no fator de transcrição PAX8. Neste estudo, foram rastreadas mutações no gene PAX8 em 50 pacientes com CH com disgenesia da tireoide. SUJEITOS E MÉTODOS: Os pacientes foram classificados em dois grupos, com agenesia ou com ectopia, segundo os testes bioquímicos e paraclínicos. Foram empregadas as técnicas de SSCP (Single Strand Conformation Polymorphism) e sequenciamento para analisar os éxons 3 a 12 do gene PAX8 e suas bordas éxon-intron. RESULTADOS: Nenhuma mutação foi encontrada nesses pacientes, em qualquer um dos éxons. CONCLUSÃO: Nossos resultados, mais uma vez, indicam que a taxa de mutação PAX8 é muito baixa e só pode explicar a minoria dos casos. Portanto, é altamente necessário investigar outros genes que controlam o desenvolvimento e as funções tireoideanas.