Detection of chromosomal abnormalities in formalin-fixed and paraffin-embedded autopsy material from fetuses using FISH

Abstract

Spontaneous abortions or intrauterine foetal deaths are in 60-70 percent of the cases caused by trisomy 13, 18, 21 or Turner syndrome. Fluorescence in situ hybridization (FISH) with centromere or locus specific probes for chromosome 13, 18, 21, X and Y was performed on formalin-fixed and paraffin-embedded material from ten aborted fetuses with suspected chromosome abnormality. A chromosome aberration was detected in four of ten cases. Two foetuses were identified as trisomy 21 (Down syndrome), one had trisomy 18 (Edward syndrome) and one female fetus had monosomy X (Turner syndrome). In six cases no abnormality was detected for any of the probes examined. Optimal pre-treatment of nuclei from autopsy material with a commercial kit (Histology FISH Accessory Kit) resulted in successful hybridization in 91.4 percent of the specimens. In cases not previously karyotyped, this pre-treatment has simplified the implementation of FISH on autopsy material.

Keywords

• fluorescence in situ hybridization
• isolated nuclei
• chromosomal abnormality
• autopsy material