Are trisomies tested in the tellmeGen DNA test?
The human genome is organised into 22 pairs of autosomal chromosomes and one pair of sex chromosomes. Thanks to sexual reproduction we receive one set of chromosomes from the mother and one from the father. We talk about chromosomal alterations when there are failures in the formation of the gametes or in the embryonic development that affect the morphology and the number of chromosomes, as it happens in the trisomy. Two examples of pathologies caused by trisomy, in which there is an extra chromosome for one of the pairs of chromosomes, would be Down’s Syndrome (chromosome 21 trisomy) or Klinefelter’s Syndrome which produces trisomy in the sex chromosomes (XXY).
The genotyping chips do not evaluate chromosomal alterations but focus on single nucleotide variations or SNPs. This technology also allows the study of small insertions and deletions that produce the addition or elimination of small fragments of DNA, which affect a few base pairs, and which do not manifest as an alteration of the chromosome structure.