title: Down syndrome: parental origin, recombination, and maternal age.
abstract: The aims of the present study were to assess (1) the parental origin of trisomy 21 and the stage in which nondisjunction occurs and (2) the relationship between altered genetic recombination and maternal age as risk factors for trisomy 21. The study included 102 cases with Down syndrome from the Croatian population. Genotyping analyses were performed by polymerase chain reaction using 11 short tandem repeat markers along chromosome 21q. The vast majority of trisomy 21 was of maternal origin (93%), followed by paternal (5%) and mitotic origin (2%). The frequencies of maternal meiotic I (MI) and meiotic II errors were 86% and 14%, respectively. The highest proportion of cases with zero recombination was observed among those with maternal MI derived trisomy 21. A higher proportion of telomeric exchanges were presented in cases with maternal MI errors and cases with young mothers, although these findings were not statistically significant. The present study is the first report examining parental origin and altered genetic recombination as a risk factor for trisomy 21 in a Croatian population. The results support that trisomy 21 has a universal genetic etiology across different human populations.
authors.affiliation: Department of Biology and Medical Genetics, School of Medicine, University of Rijeka, Rijeka, Croatia.
authors.forename: Jadranka
authors.initials: J
authors.lastname: Vraneković
authors.forename: Ivana Babić
authors.initials: IB
authors.lastname: Božović
authors.forename: Zorana
authors.initials: Z
authors.lastname: Grubić
authors.forename: Jasenka
authors.initials: J
authors.lastname: Wagner
authors.forename: Dinko
authors.initials: D
authors.lastname: Pavlinić
authors.forename: Sophie
authors.initials: S
authors.lastname: Dahoun
authors.forename: Frédérique
authors.initials: F
authors.lastname: Bena
authors.forename: Vida
authors.initials: V
authors.lastname: Culić
authors.forename: Bojana
authors.initials: B
authors.lastname: Brajenović-Milić
mesh_terms: D000293:Adolescent; D000328:Adult; D017523:Croatia; D004198:Disease Susceptibility; D004314:Down Syndrome / Q000209:etiology* / Q000235:genetics*; D005260:Female; D006801:Humans; D040582:Inheritance Patterns; D008297:Male; D008423:Maternal Age; D008540:Meiosis / Q000235:genetics / Q000502:physiology; D009630:Nondisjunction, Genetic / Q000235:genetics / Q000502:physiology; D010290:Parents; D011247:Pregnancy; D011995:Recombination, Genetic / Q000502:physiology; D012307:Risk Factors; D055815:Young Adult