Which condition falls under the category of X-linked recessive inheritance?

Which condition falls under the category of X-linked recessive inheritance?

• A. Hemophilia A
• B. Marfan syndrome
• C. Achondroplasia
• D. Huntington disease

Answer: (A)

Hemophilia A is indeed classified as an X-linked recessive condition. This type of inheritance means that the gene responsible for the disorder is located on the X chromosome and that two copies of the recessive gene are typically required for females to express the condition. Males, having only one X chromosome, are more likely to be affected by X-linked recessive conditions because they have only a single copy of the gene. Therefore, if a male inherits the affected X chromosome from his mother, he will manifest the disease. In contrast, Marfan syndrome, achondroplasia, and Huntington disease do not follow an X-linked recessive inheritance pattern. Marfan syndrome is an autosomal dominant disorder caused by mutations in the FBN1 gene on chromosome 15. Achondroplasia is also an autosomal dominant condition, arising from mutations in the FGFR3 gene. Huntington disease is an autosomal dominant disorder as well, associated with mutations in the HTT gene on chromosome 4. Understanding the pattern of inheritance is crucial for predicting how traits and conditions can be passed from parents to offspring.

Hemophilia A is indeed classified as an X-linked recessive condition. This type of inheritance means that the gene responsible for the disorder is located on the X chromosome and that two copies of the recessive gene are typically required for females to express the condition. Males, having only one X chromosome, are more likely to be affected by X-linked recessive conditions because they have only a single copy of the gene. Therefore, if a male inherits the affected X chromosome from his mother, he will manifest the disease.

In contrast, Marfan syndrome, achondroplasia, and Huntington disease do not follow an X-linked recessive inheritance pattern. Marfan syndrome is an autosomal dominant disorder caused by mutations in the FBN1 gene on chromosome 15. Achondroplasia is also an autosomal dominant condition, arising from mutations in the FGFR3 gene. Huntington disease is an autosomal dominant disorder as well, associated with mutations in the HTT gene on chromosome 4. Understanding the pattern of inheritance is crucial for predicting how traits and conditions can be passed from parents to offspring.