Sex chromosome abnormalities occur as a result of chromosome mutations brought on by mutagens like radiation or problems that occur during meiosis. One type of mutation is caused by chromosome breakage. The broken chromosome fragment may be deleted, duplicated, inverted, or translocated to a non- homologous chromosome. Another type of mutation occurs during meiosis and causes cells to have either too many or not enough chromosomes.
Frequency and distribution of chromosome abnormalities in human spermatozoa
This study reviews the frequency and distribution of numerical and structural chromosomal abnormalities in spermatozoa from normal men obtained by the human-hamster system and by multicolor-FISH analysis on decondensed sperm nuclei. Results from large sperm karyotyping series analyzed by chromosome banding techniques and results from multicolor FISH in sperm nuclei of at least 10 4 spermatozoa per donor and per probe were reviewed in order to establish baseline values of the sperm chromosome abnormalities in normal men. In karyotyping studies, the mean disomy frequency in human sperm is 0. Both types of studies coincide in that chromosome 21 and sex chromosomes have a greater tendency to suffer segregation errors than the rest of the autosomes.
The chromosomes, apart from the sex chromosomes , are known as autosomes of an organism. The number of chromosomes varies from one organism to others. In humans, there is a total of 46 chromosomes or in pair of Out of these, 2 are sex chromosome XX or XY , and 44 are autosomes.
Chromosome abnormalities can be numerical or structural. A numerical abnormality mean an individual is either missing one of the chromosomes from a pair or has more than two chromosomes instead of a pair. A structural abnormality means the chromosome's structure has been altered in one of several ways.