Chromosomal mosaicism for isochromosome 11q confined to CVS direct preparations.

OBJECTIVE

To analyse the discrepancy between the karyotype in direct preparations of chorionic villus sampling (CVS) and the fetal karyotype and its possible fetal phenotypic repercussion.

METHODS

The karyotype was obtained from direct and cultured preparations of CVS. FISH was performed in direct CVS preparations and in four different areas of term placenta.

RESULTS

Karyotype and FISH analysis in CVS revealed a 46,XX/47,XX,+i(11q) cell line. Cultured CVS preparations showed a 46,XX karyotype. Cytogenetic studies in term placenta did not reveal the abnormal cell line. Molecular studies did not detect uniparental disomy for chromosome 11 in the fetus.

CONCLUSION

The fetus, at birth, had no phenotypic abnormalities. IUGR was not present during gestation, in accordance with the low proportion of aneuploid cells in term placenta, and UPD for chromosome 11 was not observed.