X-linked dominant disorders require one copy of the mutated gene, affecting both genders. X-linked recessive disorders need both copies, affecting males more.
X-linked dominant and X-linked recessive disorders are two types of genetic conditions associated with genes located on the X chromosome.
The X chromosome carries many genes responsible for various functions in the body.
Here are the key differences between X-linked dominant and X-linked recessive disorders:
1. **Inheritance Pattern:**
- **X-Linked Dominant:** In X-linked dominant disorders, a single copy of the mutated gene on one of the X chromosomes is sufficient to express the phenotype.
Both males and females can be affected, but the manifestation may be more severe in males.
- **X-Linked Recessive:** X-linked recessive disorders require both X chromosomes to carry the mutated gene for the phenotype to be expressed.
Males are more commonly affected, as they have only one X chromosome.
2. **Expression in Males and Females:**
- **X-Linked Dominant:** Both males and females can be affected, and the symptoms may be evident in individuals with only one copy of the mutated gene.
Severity can vary between genders.
- **X-Linked Recessive:** Females are typically carriers with no or mild symptoms, while males, having only one X chromosome, often display more severe symptoms if the gene is mutated.
3. **Transmission from Parents:**
- **X-Linked Dominant:** An affected father can pass the disorder to both sons and daughters.
An affected mother has a 50% chance of passing the disorder to each child.
- **X-Linked Recessive:** Carrier mothers have a 50% chance of passing the mutated gene to their sons, who may then express the disorder.
Daughters of carrier mothers have a 50% chance of being carriers.
4. **Prevalence:**X-Linked Dominant: These disorders are relatively rare compared to X-linked recessive disorders.
- X-Linked Recessive: X-linked recessive disorders are more common, given that the mutation has to be present on the X chromosome of both parents for males to be affected.
Question
What is the difference between X-linked dominant and X-linked recessive disorders?