Absence of clotting factor protein in blood with vulnerability to hemorrhage and severe joint damage is characteristic of which condition?

• A. Huntington disease
• B. Hemophilia
• C. X-linked disorders
• D. Cystic fibrosis

Answer: (B)

A deficiency of a blood clotting factor leads to abnormal bleeding and, with repeated bleeding into joints, severe joint damage. This pattern fits hemophilia, in which the body lacks sufficient clotting factor VIII (hemophilia A) or IX (hemophilia B). Without these factors, the coagulation cascade can’t form a proper clot, so even minor injuries cause prolonged bleeding and can cause blood to accumulate in joints, causing pain and damage over time. Hemophilia is typically inherited as an X-linked recessive condition, which explains why it often appears in males and can run in families.

Huntington disease is a neurodegenerative disorder with motor, cognitive, and behavioral symptoms, not primarily a clotting problem. Cystic fibrosis involves a defect in a chloride channel affecting mucus production and organ function, not clotting. Saying “X-linked disorders” is too broad a descriptor and doesn’t specify the clotting-factor deficiency responsible for this bleeding pattern.