Definition - What does Chromosome Deletion mean?
Chromosome deletion occurs when a loss of a part of a chromosome is evident microscopically. This break in the chromosome results in alteration of genetic code. The chromosome deletion can indicate a genetic mutation or at times result in an entire missing section of a chromosome causing genetic diseases and syndromes. This can affect any chromosome in any cell of the body, but when it involves Y chromosome (sex chromosome in males), it results in infertility.
Chromosome deletion is also called gene deletion or deletion mutation.
FertilitySmarts explains Chromosome Deletion
Every cell in the human body has a pair of sex chromosomes, XX for females and XY for males. The Y chromosome in males is inherited from the father and is responsible for sex determination and development. Chromosome deletion involving specific regions of this Y chromosome results in Y chromosome infertility as the genes in these regions direct production of proteins required for the production of sperm cells. Men affected by this may experience:
- Azoospermia - absence of sperm
- Oligozoospermia - mildly, moderately or severely low sperm count
- Teratozoospermia - abnormal shape or motility of sperm cells.
Y chromosome infertility is suspected when one of the above-mentioned sperm abnormalities is present and all the other causes have been ruled out. Diagnostic tests like cytogenic and molecular tests can confirm the cause.
Treatment to contribute to a pregnancy generally involves the use of in vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI) where sperm cells are extracted from either ejaculate (if oligozoospermia) or testicular biopsies (if azoospermia) and injected into retrieved eggs.