Abstract
We determined the meiotic origin and the stage of non-disjunction of the extra X chromosomes in two sisters with 47,XXX chromosomal complements. Segregation of the X chromosomes in all family members was analyzed using X-linked short tandem repeat polymorphic (STRP) markers. Densitometric analysis of two STRP markers confirmed that both sisters had three copies of the X chromosome and the extra X chromosomes were maternally derived. Both sisters did not share the same maternal homologue suggesting that the recurrent trisomy is non-homologous X chromosome-specific. Haplotype analysis demonstrated a reduction to homozygosity for markers examined, covering most of the length of the X chromosomes in both sisters. These findings suggested that the extra X chromosomes have derived from meiotic II non-disjunction following a nullitransitional meiosis I (MI). A lack of recombination in the X chromosomes of both sisters suggests a possible maternal genetic defect leading to an erratic recombination at MI. This information may contribute to further understanding of mechanisms leading to X chromosome non-disjunction and may assist in counseling of families with this chromosomal rearrangement.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 125-132 |
| Number of pages | 8 |
| Journal | Chromosome Research |
| Volume | 12 |
| Issue number | 2 |
| DOIs | |
| State | Published - 2004 |
Bibliographical note
Funding Information:This work was supported in part by grant M01-RR00400, from the National Institutes of Health to the General Clinical Research Center.
Keywords
- Meiosis I
- Meiosis II
- Non-disjunction
- Recombination
- Trisomy X