Table 1. Summary of the results of the prospective study on 4000 AF samples.
| MLPA result | n | Chromosome result | n |
|---|---|---|---|
| Conclusive | (3932) | ||
| Normal male/female | 3783 | Normal 46,XY or 46,XX | 3707 |
| Abnormal | 76 | ||
| 69,XXX | 4 | ||
| mos 47,XXY[5]/(47,XXY/46,XY)[1]/46,XY[45] | 1 | ||
| mos 45,X[5]/(45,X/46,XY)[1]/46,XY[20] | 1 | ||
| (mos) 47,+ mar | 8 | ||
| (mos) aneuploidy (no 13, 18, 21, X, Y) | 6 | ||
| Structural chromosome aberration | 56 | ||
| Abnormal | |||
| 1. Common aneuploidies | |||
| Trisomy 21 | 75 | 47,XX or XY,+21 | 75 |
| Trisomy 18 | 24 | 47,XX or XY,+18 | 24 |
| Trisomy 13 | 17 | 47,XX or XY,+13 | 16 |
| 46,XX,+13,der(13;14)(q10;q10)pat | 1 | ||
| Monosomy X | 8 | 45,X | 8 |
| Triple X | 3 | 47,XXX | 3 |
| XXY | 8 | 47,XXY | 8 |
| XYY | 1 | 47,XYY | 1 |
| Triploidy XXY | 3 | 69,XXY | 3 |
| 2. Other aberrations | |||
| 2a. Mosaics | |||
| mos XXY/XY | 1 | mos 47,XXY[6]/46,XY[21] (22%) | 1 |
| mos XYY/XY | 1 | mos 45,X[2]/46,XY[12] (14%)a | 1 |
| mos X/XY | 3 | mos 45,X[63]/46,XY[2] (97%) | 1 |
| mos 45,X[12]/46,XY[8] (60%) | 1 | ||
| mos 45,X[15]/(45,X/46,XY)[3]/46,XY[25] (39%) | 1 | ||
| mos XY,+21 | 1 | mos 47,XY,+21[8]/46,XY[25] (24%) | 1 |
| mos XY,+18 | 1 | 47,XY,+18b | 1 |
| 2b. Structural chromosome aberrations | |||
| amp(13) (CCNA) | 1 | 46,XX,der(17)ins(17;13)(q11.2;q12.3q14.1)mat | 1 |
| del(21) (USP25, STCH) | 1 | 45,XX,der(4)inv(4)(p16q35)t(4;21)(q35;q11),-21 | 1 |
| del(18) (TYMS) | 1 | 46,XX.ish del(18)(p11.32p11.32)(RP11-145B19-)c | 1 |
| Inconclusive | (68) | ||
| Potential MCC | 58 | 46,XX | 51 |
| 46,XY | 3 | ||
| mos 47,XX,+2[11]/46,XX[14] (44%) | 1 | ||
| 69,XXX | 1 | ||
| 46,XX,inv(13)(q14.2q21.1)pat | 1 | ||
| 46,XX,t(9;20)(q32;p13)pat | 1 | ||
| Insufficient amount of DNA | 8 | 46,XX | 3 |
| 46,XY | 4 | ||
| 47,XXY | 1 | ||
| Unknown reasons | 2 | 46,XY | 2 |
| Total | 4000 | 4000 |
a
The mosaic XYY/XY with MLPA and QF-PCR showed to be a mosaic 45,X/46,XY in the cell cultures. An explanation might be that both abnormal cell lines are the products of non-disjunction of an XY cell during early embryonic development with selection against the XYY cell line in AF cell cultures.
b
With FISH on uncultured AF cells, a mosaic trisomy 18 was found as well, with 26% of the cells showing three signals. The karyotype was 47,XY,+18 in 61 cell clones.
c
The deletion was confirmed with FISH with an overlapping BAC clone RP11-145B19.