The origin of trisomy 13

Abstract

Trisomy 13 is one of the most common trisomies in clinically recognized pregnancies and one of the few trisomies identified in liveborns, yet relatively little is known about the errors that lead to trisomy 13. Accordingly, we initiated studies to investigate the origin of the extra chromosome in 78 cases of trisomy 13. Our results indicate that the majority of cases (>91%) are maternal in origin and, similar to other autosomal trisomies, the extra chromosome is typically due to errors in meiosis I. Surprisingly, however, a large number of errors also occur during maternal meiosis II ( approximately 37%), distinguishing trisomy 13 from other acrocentric and most nonacrocentric chromosomes. As with other trisomies, failure to recombine is an important contributor to nondisjunction of chromosome 13.

Chromosomal and cytoplasmic context determines predisposition to maternal age-related aneuploidy: brief overview and update on MCAK in mammalian oocytes

“…Under the condition that such oocytes are developing slowly, survive in primordial follicles and become recruited for resumption of maturation only late in the reproductive period according to a production line [5] they could contribute to increases in numbers of aneuploid oocytes in older females. In normal diploid oocytes the absence of exchanges or placement, and the numbers of crossing overs that are established in the embryonic ovary, may also relate to the relative risk of each individual chromosome undergoing nondisjunction or facilitating normal distribution after resumption of maturation in the cytoplasm of an aged oocyte [11][12][13]. This means that there is a link between early and late events in oogenesis.…”

“…Lastly, there are different hypotheses on constitutive and age-related alterations in the hormonal homoeostasis, and in oocytes and follicles, which are believed to correlate with increased failures in faithful and sequential segregation of homologues and sister chromatids at meiosis I and II in oocytes [9]. In Figure 1 Stages of oogenesis that are susceptible to disturbances and events leading synergistically to high risks for errors in chromosome segregation in oocytes at advanced maternal age (A) Events in the embryonic ovary, including presence of trisomic cell line of oogonia [10], failure to recombine and/or numbers and placement of exchanges on homologous chromosomes [8,[11][12][13]. (B) Events during long meiotic arrest of dictyate stage-arrested oocyte in the primordial follicle post-birth, including accumulation of insult by environment, life style/nutrition and ROS, loss of cohesion during chronological ageing and reduction of follicle pool (physiological ageing) by continuous recruitment and atresia of follicles [5][6][7][16][17][18][19][20][21][22].…”

Prenatal diagnosis of a partial trisomy 13q (q14→qter): phenotype, cytogenetics and molecular characterization by spectral karyotyping and array comparative genomic hybridization

“…The majority of trisomy 13q cases (>90%) are from maternal origin (Hall et al, 2007), typically due to errors in meiosis I, as in other autosomal trisomies. Many cases are from parental balanced translocations, typically as pericentric inversions.…”

“…It has been described as having a variable phenotypic expression. It may result from parental reciprocal translocations, parental pericentric inversions (Chen et al, 2005b) or de novo direct duplications (Hall et al, 2007).…”

Trisomy 13 (Sy Patau)

“…Klinički se ovaj sindrom karakteriše vrlo teškim malformacijama mozga (arinencefalija), očiju (mikroftalmija ili anoftalmija), rascepima usne, vilice i nepca (heliognatopalatoshiza), polidaktilijom (veći broj prstiju), anomalijama srca (defekti septuma), bubrega (cistični bubrezi, potkovičasti bubrezi) i digestivnog PRIKAZI SLUČAJA trakta (malrotacije creva) 4,5,6 . Preživljavanje preko nekoliko nedelja je veoma retko, a 50% dece umire u prva tri dana života.…”