When a person is missing a chromosome, it is called monosomy.
Understanding Monosomy
Monosomy is a type of chromosomal abnormality where an individual has only one copy of a particular chromosome instead of the usual two copies. This means they are missing one chromosome from the pair. This condition can occur in either the sex chromosomes (X and Y) or the autosomes (non-sex chromosomes).
Key Features of Monosomy
- Missing Chromosome: The core characteristic is the absence of one chromosome from a pair.
- Chromosomal Abnormality: Monosomy falls under the broader category of chromosomal abnormalities.
- Potential for Health Issues: Due to the genetic imbalance, monosomy often leads to a range of health complications, the severity of which can vary depending on the specific chromosome involved.
Monosomy vs. Other Chromosomal Conditions
It's important to distinguish monosomy from other conditions involving chromosome numbers:
| Condition | Chromosome Count | Description |
|---|---|---|
| Monosomy | 2n-1 | Missing one chromosome from a pair. |
| Trisomy | 2n+1 | Having an extra chromosome. |
| Euploidy | n | Normal chromosome count. |
| Polyploidy | >2n | Having more than two sets of chromosomes. |
| Aneuploidy | Abnormal | Having an abnormal number of chromosomes (includes monosomy and trisomy) |
Examples of Monosomy
- Turner Syndrome: A common example of monosomy, involving a single X chromosome in females (45, X). Individuals with Turner syndrome may experience developmental issues, including short stature and ovarian failure.
Implications of Monosomy
- Developmental Problems: The absence of a chromosome can disrupt normal development.
- Health Issues: Monosomy is often associated with various health problems that require specialized medical care.
- Genetic Counseling: Genetic counseling is essential for families affected by monosomy to understand risks and options.
In summary, monosomy is the term for when a person is missing one chromosome from a pair.
