This paper is only available as a PDF. To read, Please Download here.
Tabled
1Table 2b: Percentages
| N of embs | N/B | UNB | ABN | NR | |
|---|---|---|---|---|---|
| INS | 68 | 22.06% | 47.06% | 27.94% | 2.94% |
| REC + DEL | 6 | 0.00% | 50.00% | 16.67% | 33.33% |
| REC + INS | 68 | 4.41% | 88.24% | 0.00% | 7.35% |
| REC + INV | 96 | 20.83% | 69.79% | 3.13% | 6.25% |
| REC + ROB | 104 | 4.81% | 95.19% | 0.00% | 0.00% |
| REC XX + REC XY | 16 | 25.00% | 62.50% | 12.50% | 0.00% |
| RECx2 | 34 | 2.94% | 64.71% | 17.65% | 14.71% |
| ROB + INV | 8 | 62.50% | 12.50% | 25.00% | 0.00% |
| TWT | 117 | 12.82% | 76.07% | 5.13% | 5.98% |
| Total | 517 | 13.15% | 74.08% | 7.54% | 5.22% |
Background
Patients with structural chromosome rearrangements encounter a variety of reproductive
obstacles as a result of the high frequency of unbalanced gametes in these individuals,
including low pregnancy rates, increase in spontaneous abortion (SAB) rate and an
increased risk for unbalanced, genetically abnormal offspring1. The most common structural
chromosome abnormality is the reciprocal translocation, seen in about 0.16% of the
general population. A reciprocal translocation is the exchange of genetic material
between two chromosomes; it is estimated that approximately 70% of embryos generated
by a parent with a reciprocal translocation are abnormal. The next two most common
structural chromosome abnormalities are Robertsonian translocations (0.1% of the general
population) and inversions (0.02% of the general population).
Other cases of structural chromosome abnormalities are less common, more complex,
and supposedly precipitate the chances to have a successful outcome. Due to the scarcity
of these cases these structural abnormalities have been poorly studied.
For this study we include the chromosomal structural abnormalities classified as insertions
and complex chromosome rearrangements (CCRs). Insertions are the relocation of a region
of a chromosome to another location of the genome (whether the same chromosome or
other chromosome), and CCRs are structural chromosome abnormalities involving three
or more chromosomes.
This study aims to determine the proportion of unbalanced embryos and reproductive
risk to patients carrying insertions or CCR.
Materials and methods
This study collects data from insertion and CCR cases analyzed by PGD techniques available
at the time the case was processed. These techniques are fluorescence in situ hybridization
(FISH), array comparative genome hybridization (aCGH), and next generation sequencing
(NGS).
Tabled
1Table 1: Types of abnormalities for this study
| Structural abnormality | Acronym | Number of patients | Number of cycles |
|---|---|---|---|
| Insertion | INS | 8 | 12 |
| Reciprocal translocation and deletion | REC + DEL | 1 | 1 |
| Reciprocal translocation and insertion | REC + INS | 1 | 4 |
| Reciprocal translocation and inversion | REC + INV | 5 | 7 |
| Reciprocal translocation and Robertsonian translocation | REC + ROB | 3 | 8 |
| Male carrier reciprocal translocation and Female carrier of reciprocal translocation | REC XX + REC XY | 2 | 3 |
| Two reciprocal translocation in one carrier | RECx2 | 3 | 7 |
| Robertsonian translocation and inversion | ROB + INV | 1 | 1 |
| Three way translocation | TWT | 8 | 15 |
| Total | 32 | 58 |
32 patients were included in this studies, from which 58 cycles were performed, and
517 embryos were analyzed
Results
Tabled
1Table 2a: Number of embryos and type of embryos
| N of embs | N/B | UNB | ABN | NR | |
|---|---|---|---|---|---|
| INS | 68 | 15 | 32 | 19 | 2 |
| REC + DEL | 6 | 0 | 3 | 1 | 2 |
| REC + INS | 68 | 3 | 60 | 0 | 5 |
| REC + INV | 96 | 20 | 67 | 3 | 6 |
| REC + ROB | 104 | 5 | 99 | 0 | 0 |
| REC XX + REC XY | 16 | 4 | 10 | 2 | 0 |
| RECx2 | 34 | 1 | 22 | 6 | 5 |
| ROB + INV | 8 | 5 | 1 | 2 | 0 |
| TWT | 117 | 15 | 89 | 6 | 7 |
| Total | 517 | 68 | 383 | 39 | 27 |
To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to Reproductive BioMedicine OnlineAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
Article info
Identification
Copyright
© 2019 Published by Elsevier Inc.
