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Sex-linked dominant
Definition Sex-linked dominant is a rare way that a trait or disorder can be passed down through families. A single abnormal gene on the X chromosome can cause a sex-linked dominant disease. Related terms and topics: - Gene
- Chromosome
- Inheritance
- Heredity and disease
- Genetic counseling and prenatal diagnosis
- Sex-linked recessive
- Autosomal dominant
- Autosomal recessive
Alternative Names Inheritance - sex-linked dominant; Genetics - sex-linked dominant; X-linked dominant Information Inheritance of a specific disease, condition, or trait depends on the type of chromosome affected (autosomal or sex chromosome) whether the trait is dominant or recessive. Sex-linked diseases are inherited through one of the sex chromosomes (the X or Y chromosome). Dominant inheritance occurs when an abnormal gene from ONE parent is capable of causing disease even though there may be a matching gene from the other parent that is normal. The abnormal gene dominates the outcome of the gene pair. For an X-linked dominant disorder: If the father carries the abnormal X gene, all of his daughters will inherit the disease and none of the sons will have the disease. If the mother carries the abnormal X gene half of all their children (daughters and sons) will inherit the disease tendency. In other words, if it is assumed that 4 children are produced (2 male and 2 female) and the mother is affected (1 abnormal X, she has disease) but the father is not, the STATISTICAL expectation is for: - 2 children (1 girl and 1 boy) with disease
- 2 children (1 girl and 1 boy) without the disease
If it is assumed that 4 children are produced (2 male and 2 female) and the father is affected (abnormal X, he has disease) but the mother is not, the STATISTICAL expectation is for: - 2 girls with disease
- 2 boys without the disease
This does not mean that children WILL necessarily be affected. Review date: 6/25/2007 Reviewed By: Chad Haldeman-Englert, MD, Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA. Review provided by VeriMed HealthcareNetwork.
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