Relevant markers for molecular diagnosis of 46,XX SRY-positive azoospermic men

• Autor(es): Pereira-Caetano, Iris ; Gonçalves, João
• Data: 2021
• Identificador Persistente: http://hdl.handle.net/10400.18/8134
• Origem: Repositório Científico do Instituto Nacional de Saúde
• Assunto(s): 46,XX male; SRY; Doenças Genéticas; Azoospermia
• Tipo de Documento: Objeto de conferência
• Idioma: Inglês
• Contribuidor(es): Repositório Científico do Instituto Nacional de Saúde

Descrição

Introduction: Molecular screening of Y-chromosome AZF microdeletions, along with chromosome analysis, is the first step of the genetic diagnosis routinely performed in infertile men with severe oligozoospermia or non-obstructive azoospermia. These deletions can cover one or more of the three AZF regions, each one with different testicular histological phenotypes ranging from Sertoli cell only (SCO) syndrome (AZFa) to gamete maturation arrest (AZFb) and hypospermatogenesis (AZFc). Complete AZF deletions (AZFabc) are very rare and most likely related to abnormal karyotypes such as 46,XX, 46,X,del(Y)(q11.1) or 46,X,iso(Y)(p10), causing azoospermia with SCO, therefore it is not appropriate to propose testicular sperm extraction due to the impossibility to retrieve testicular spermatozoa for intracytoplasmic sperm injection. Methodology: Since 2000, we analysed 348 samples of azoospermic men, in compliance with EAA/EMQN best practice guidelines for Y-chromosomal microdeletions testing1, and participated annually in the EMQN-EQA programs. Genomic DNA was analysed by multiplex-PCR amplification of STS specific for each AZF region, and SRY and AR (in Xq12) as control markers. In case of AZFabc deletions, an extension PCR-analysis was performed for DYZ3 Y-centromere marker: if present other Yq centromeric proximal border markers were screened; if DYZ3 was absent (most cases of 46,XX males SRY-positive) other Yp specific genes were screened (RPS4Y, ZFY, AMELY, PRKY) in order to characterize the Yp segment. Results/Discussion: We characterized 10 men with AZFabc deletions, 8 of which 46,XX SRYpositive, negative for the centromere and all the AZFabc markers. In these cases, screening for heterochromatin (e.g. sY160) and markers mapping between the centromere and AZFa is inappropriate, as it is highly unlikely that these patients have Yq material between AZFa and the centromere and terminal Yq sequences. Testing for the presence of additional markers besides those used in our methodology do not have any relevance for the diagnosis nor the clinical management of these patients. In such cases, karyotyping evaluation is recommended. 1- Krausz et al 2014, Andrology; 2(1): 5–19