X-linked dominant

X-linked dominant is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome. As an inheritance pattern, it has implications for genetics, medical genetics and research.

Overview

X-linked dominant inheritance occurs when a gene responsible for a trait or disorder is located on the X chromosome, one of the two sex chromosomes in each cell. In females (who have two X chromosomes), a mutation in one of the two copies of the gene in each cell is sufficient to cause the trait or disorder. In males (who have only one X chromosome), a mutation in the only copy of the gene causes the trait or disorder.

Characteristics

X-linked dominant disorders are caused by mutations in genes on the X chromosome. Only a few disorders have this inheritance pattern, with a prime example being Rett syndrome. Other examples of X-linked dominant disorders include Incontinentia pigmenti, Hypophosphatemic rickets, and Aicardi syndrome.

Inheritance

In X-linked dominant inheritance, a female with a mutation in one copy of a gene on one of her X chromosomes (heterozygous) can pass on the mutation to her sons and daughters. Her sons will be affected because they only have one X chromosome, and it carries the mutation. Her daughters have a 50% chance of inheriting the mutation and being affected by the disorder.

Diagnosis and Testing

Diagnosis of X-linked dominant disorders can be challenging, as the manifestation of the disorder can vary greatly among individuals. Genetic testing can be used to identify mutations in the X chromosome that indicate an X-linked dominant disorder.

Treatment and Management

Treatment for X-linked dominant disorders varies depending on the specific disorder and the symptoms present. It often involves managing symptoms and improving quality of life.

See also

• Genetic disorder
• X-linked recessive inheritance
• Y-linked inheritance
• Zygosity

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