title: Unique t(Y;1)(q12;q12) reciprocal translocation with loss of the heterochromatic region of chromosome 1 in a male with azoospermia due to meiotic arrest: a case report.
abstract: A de novo reciprocal translocation 46,X,t(Y;1)(q12;q12) was found in an azoospermic male with meiotic arrest. Cytogenetics and fluorescent in situ hybridization (FISH) were used to define the karyotype, translocation breakpoints and homologue pairing. SRY (Yp), Yq11.2-AZF regions, DAZ gene copies and the distal Yq12 heterochromatin were studied by PCR and restriction analysis using sequence-tagged sites and single nucleotide variants. High resolution GTL, CBL and DA-DAPI staining revealed a (Y;1) translocation in all metaphases and a normal karyotype in the patient's father. FISH showed the presence of the distal Yq12 heterochromatic region in der(1) and loss of the heterochromatic region of chromosome 1. PCR demonstrated the intactness of the Y chromosome, including the SRY locus, AZF regions, DAZ genes and distal heterochromatin. A significant decrease (P = 0.005) of Xp/Yp pairing (18.6%), as compared with controls (65.7%), was found in arrested primary spermatocytes, and cell culture and mRNA expression studies confirmed an irreversible arrest at meiosis I, with induction of apoptosis and removal of germ cells by Sertoli cells. We characterized a de novo t(Y;1)(q12;q12) balanced reciprocal translocation with loss of the heterochromatic region of chromosome 1, that caused unpairing of sex chromosomes followed by meiosis I arrest, apoptotic degeneration of germ cells and azoospermia.
authors.affiliation: Department of Genetics, Faculty of Medicine, ICBAS, University of Porto, Portugal.
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Pinho
authors.forename: Rui
authors.initials: R
authors.lastname: Neves
authors.forename: Paula
authors.initials: P
authors.lastname: Costa
authors.forename: Cristina
authors.initials: C
authors.lastname: Ferrás
authors.forename: Mário
authors.initials: M
authors.lastname: Sousa
authors.forename: Cláudia
authors.initials: C
authors.lastname: Alves
authors.forename: Carolina
authors.initials: C
authors.lastname: Almeida
authors.forename: Susana
authors.initials: S
authors.lastname: Fernandes
authors.forename: Joaquina
authors.initials: J
authors.lastname: Silva
authors.forename: Luís
authors.initials: L
authors.lastname: Ferrás
authors.forename: Alberto
authors.initials: A
authors.lastname: Barros
mesh_terms: D000328:Adult; D017209:Apoptosis; D002478:Cells, Cultured; D002878:Chromosomes, Human, Pair 1 / Q000235:genetics*; D041322:Chromosomes, Human, Y / Q000235:genetics*; D020732:Cytogenetic Analysis; D017353:Gene Deletion; D006570:Heterochromatin / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D008540:Meiosis; D009845:Oligospermia / Q000235:genetics / Q000503:physiopathology*; D013094:Spermatozoa; D014178:Translocation, Genetic
chemical_list: D006570:Heterochromatin