title: Heterochromatin variants in human karyotypes: a possible association with reproductive failure.
abstract: Heterochromatin variants are commonly found during cytogenetic examinations, and chromosomes 1, 9, 16 and Y are commonly involved in these variations. These variants are believed to be clinically insignificant variations in human karyotypes. Nevertheless, reproductive failure has been frequently discussed as possibly being associated with these variants. Various authors have reported a significantly elevated incidence of these variants in individuals with idiopathic reproductive failure compared with individuals with no such history. This study compared the incidence of heterochromatin variants in individuals with idiopathic reproductive failure (n=1036) with that of a control group of healthy fetuses (n=995) indicated for prenatal karyotype examination solely based on the advanced ages of their mothers. The heterochromatin variants occurred more frequently in the reproductive failure group than in the controls (P=0.006). Regarding individual chromosomes, chromosome 9 variants were most frequently found in the study and control groups, and they also occurred more frequently in the reproductive failure group. The most significant difference between the study and control groups was found for the 9qh+ variant (P=0.026), and although the results are statistically significant, the cause of this phenomenon remains unknown.
authors.affiliation: Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital, Albertov 4, Prague 2, 128 00, Czech Republic. Electronic address: antonin.sipek@lf1.cuni.cz.
authors.forename: Antonín
authors.initials: A
authors.lastname: Šípek
authors.affiliation: Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital, Albertov 4, Prague 2, 128 00, Czech Republic.
authors.forename: Romana
authors.initials: R
authors.lastname: Mihalová
authors.affiliation: Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital, Albertov 4, Prague 2, 128 00, Czech Republic.
authors.forename: Aleš
authors.initials: A
authors.lastname: Panczak
authors.affiliation: Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital, Albertov 4, Prague 2, 128 00, Czech Republic.
authors.forename: Lenka
authors.initials: L
authors.lastname: Hrčková
authors.affiliation: Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital, Albertov 4, Prague 2, 128 00, Czech Republic.
authors.forename: Mimoza
authors.initials: M
authors.lastname: Janashia
authors.affiliation: Institute of Biophysics and Informatics, First Faculty of Medicine, Charles University, Salmovská 1, Prague 2, 128 00, Czech Republic.
authors.forename: Nikola
authors.initials: N
authors.lastname: Kaspříková
authors.affiliation: Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital, Albertov 4, Prague 2, 128 00, Czech Republic.
authors.forename: Milada
authors.initials: M
authors.lastname: Kohoutová
mesh_terms: D005260:Female; D006570:Heterochromatin / Q000235:genetics*; D006801:Humans; D007247:Infertility, Female / Q000235:genetics*; D007248:Infertility, Male / Q000235:genetics*; D007621:Karyotyping; D008297:Male; D012189:Retrospective Studies
chemical_list: D006570:Heterochromatin
keywords: chromosomes; cytogenetic variants; heterochromatin; infertility