Fluorescent in situ hybridization (FISH) is a diagnostic test that is performed to observe alterations in the number of chromosomes of sperm (aneuploidy). It has been observed that the presence of a high percentage of sperm with alterations in the number of chromosomes is related to alterations in the seminogram and poor results in assisted reproduction techniques.
Using FISH we can study up to 9 chromosomes (13, 18, 21, X and Y, 15,16,17 and 22), for this purpose a union of each chromosome is made to a probe, which will emit a fluorescence and thus we will know how many copies of the Chromosome will present the sperm. The sperm must present 1 single copy of each chromosome. Later the sample is compared with a control sample of what is considered normal, to establish the degree of alteration.
- Low seminal quality (OA, OAT, AT)
- Altered karyotype
- Repeat abortions.
- Failures of fertilization.
- Implementation failures.
- Chromosomal abnormalities in embryos.
- Slow embryonic development, embryonic block.
- Preclinical abortions or previous conceptions with genetic alterations.
When dealing with gametes, it is normal to have a haploid endowment (1 single copy of each of the 22 autosomes and a sex chromosome).
• Aneuploidy: gain or loss of one or more chromosomes
- Nulisomy: no copy of any chromosome
- Disomy: 2 copies of some chromosome
• Diploidy: 2 copies of all chromosomes
• A result above the norm is related to defects in spermatogenesis, andwith a relative risk in relation to embryos that are generated in vitro by techniques ofAssisted reproduction. The higher the percentage of aneuploidy the greater the risk ofreproductive of the sample.