Saturday, July 5, 2008

Chromosomal Abnormalities

Little has been explained about chromosomal abnormalities as a cause in miscarriage. When I first had mine own share of experience, my OB GYN then just told me "chromosomal abnormalities". She did not even care to expound.

Parental chromosomal abnormalities

Less commonly, the male or female parent may have a different type of abnormality in their own chromosomes that causes miscarriage in a fetus. This type of chromosome abnormality is called a translocation abnormality.Translocations occur when a portion of two different chromosomes, for example chromosomes number 13 and 21, have "swapped" positions with each other. The result (from our example) is that a little piece of chromosome 13 is now on chromosome 21 and a little piece of 21 is now on chromosome 13.This can occur in the chromosomes of the egg or the sperm.When fertilization occurs in these couples, a few different possible outcomes may occur:
  • The embryo may be completely normal
  • The embryo may end up with a balanced amount of chromosome material and end up like the parent, essentially, a carrier of the problem
  • The embryo may end up with an unbalanced amount of chromosomal material. These embryos, like the aneuploidies will be miscarried.These abnormalities can be detected with a fetal karyotype analysis unless the amount of swapped information is very small. These micro translocations (also called telomeric translocations) will be missed by standard karyotype techniques


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