Detection of two equine trisomies using SNP-CGH

Area of Science:

• Veterinary Genetics
• Comparative Genomics
• Animal Reproduction

Background:

• Chromosomal aberrations in horses lead to congenital abnormalities, embryonic loss, and infertility.
• Traditional diagnostic methods include karyotyping and Fluorescence In Situ Hybridization (FISH).
• SNP array comparative genome hybridization (SNP-CGH) is a high-resolution technique increasingly used in human diagnostics.

Purpose of the Study:

• To evaluate the efficacy of SNP-CGH for detecting chromosomal aneuploidies in horses.
• To compare SNP-CGH results with conventional karyotyping and FISH analysis.
• To investigate two equine cases with suspected chromosomal abnormalities using SNP-CGH.

Main Methods:

• Genotyping of eight horses (two with suspected abnormalities, six with confirmed aberrations) using the Equine SNP50 array.
• Analysis of normalized probe intensities and allelic ratios to detect copy number changes.
• Comparison of SNP-CGH findings with existing karyotype and FISH data.

Main Results:

• SNP-CGH results for six horses with known aberrations completely agreed with previous FISH and karyotype analyses.
• One undiagnosed case showed altered allelic ratios on chromosome 27, indicative of mosaic trisomy.
• The second undiagnosed case exhibited significant changes on chromosome 30, consistent with complete trisomy.

Conclusions:

• SNP-CGH is a viable and accurate method for detecting chromosomal aneuploidies in horses.
• This technique provides higher resolution than conventional karyotyping for equine genetic diagnostics.
• SNP-CGH can identify specific chromosomal abnormalities, aiding in the diagnosis of infertility and congenital issues in horses.