MRCP UK EXAMINATIONS

Detailed explanation-1: -Hemophilia B is the second most common type of hemophilia. 1, 2. It is also known as factor IX deficiency, or Christmas disease. It was originally named “Christmas disease” after the first person diagnosed with the disorder back in 1952.

Detailed explanation-2: -Hemophilia B, also called factor IX (FIX) deficiency or Christmas disease, is a genetic disorder caused by missing or defective factor IX, a clotting protein. Although it is passed down from parents to children, about 1/3 of cases are caused by a spontaneous mutation, a change in a gene.

Detailed explanation-3: -Factor IX (FIX, Christmas factor) is a blood clotting factor, a zymogen of serine protease. Upon activation, FIX is converted into the active serine protease and, in the presence of Ca 2+ and membrane phospholipids, it hydrolyses one arginine-isoleucine bond in factor X to form the activated factor X (Xa) [1].

Detailed explanation-4: -Clotting factor IX is referred to by the name ‘Christmas factor’.

Detailed explanation-5: -Factor Ix deficiency (PTC deficiency, Christmas disease, hemophilia B) is a congenital, often familial, hemorrhagic disorder which was distinguished from classical hemophilia (AHG deficiency, factor VIII deficiency, hemophilia A) in 1952.