Cytogenetical diagnosis in paraffin-embedded fetoplacental tissue using comparative genomic hybridization

Comparative genomic hybridization (CGH) is a FISH-related technique used to assess global chromosomal aberrations in a variety of human tumours. Recen tly CGH has been applied to cytogenetic analysis of fresh frozen fetoplacen tal tissues. Here we report the application of CGH to paraffin-embedded pla cental samples. Ten samples from paraffin-embedded blocks of 6 control plac entas and fetoplacental tissue from 10 aneuploidies, and 2 unbalanced aberr ations were evaluated. Balanced karyotype profiles were obtained from sampl es of healthy placentas and all samples from the same placenta appeared to have similar confidence intervals. CGH analysis of four cases of trisomy 21 , three cases of trisomy 18, one case of trisomy 13, one case of trisomy 15 and one case of trisomy 7 all showed overrepresentation of the respective trisomic chromosome. The CGH profile was also in accordance with the karyot yping of a case with isochromosome 21. The CGH profile of a case with der ( 2)t(2;6)(q37.3;q22.2) revealed partial trisomy for chromosome 6 between q21 and q27. CGH may be a useful adjunct in prenatal genetic diagnosis when re trospective diagnosis is needed from archival samples. Copyright (C) 2000 J ohn Wiley & Sons, Ltd.