Christmas disease or hemophilia B is when the blood is lacking factor IX, a very important clotting protein. According to experts like Best Hematologist in Lahore this is a genetic condition, i.e. it is passed down from the parents to the children. In only one-third of the cases, there is spontaneous mutation in the genes that can cause the disease. Read on to know more about Christmas disease and its pathophysiology:

What is Christmas disease?

This is a rare genetic disorder, in which blood factor IX responsible for clotting is not made by the body, resulting in impaired clotting of blood. Consequently, there is prolonged or increased bleeding and sometimes even spontaneous bleeding in the body. This disease is named after Stephen Christmas, the scientist who discovered it, and is also called hemophilia B or factor IX deficiency.According to the National Hemophilia Foundation, about two-thirds of the cases of Christmas disease are inherited, while the remaining one-third are due to spontaneous mutation of the genes during the fetal period. Without treatment, Christmas disease can be fatal.

What are the genetics of Christmas disease?

The gene for Christmas disease is carried on the X-chromosome and as a result this disease is present predominantly in male children. This is because the genetic makeup of males is made up of one X (from the mother) and one Y chromosome (from the father). If the male baby inherits the defected gene from the mother, he will produce insufficient factor IX and suffer from Christmas disease.On the other hand, genetic makeup of females is made up of two X chromosomes, one from each parent. Even if females inherited a defected X-chromosome, they can produce sufficient factor IX from the other X chromosome. However, this amount is less than normal and predisposes to heavy menstruation and easy bruising. It is very rare for a female child to inherit mutated X-chromosome from both parents. Although if it does occur, the female child will have Christmas disease.A father suffering from Christmas disease cannot pass the disease to his sons, but will pass the defective gene to his daughters—called carriers. The chances of carriers passing the disease to their babies is high, and with each pregnancy they can have a:

• 25 percent of their son having Christmas disease or 25 percent chance of their son being unaffected.
• 25 percent chance of their daughter being a carrier or 25 percent chance of their daughter being unaffected.

Thus, if there is a mother with a carrier gene, it is not always necessary for the babies to inherit the disease.

What are the symptoms of Christmas disease?

In severe cases of Christmas disease, the diagnosis is made at an early age—usually less than one year of age. For milder cases, however, the diagnosis can be delayed even as far as adulthood.In mild cases of Christmas disease, there is around 6 to 49 percent factor IX in the blood. These people can:

• Experience prolonged bleeding only after severe trauma or surgery
• Women with mild Christmas disease can have menorrhagia and hemorrhage after childbirth.

In moderate Christmas disease, there is 1 to 5 percent factor IX in the blood. Such people can:

• Have spontaneous bleeding episodes
• Excessive bleeding after minor injuries

In severe Christmas disease, there is less than 1 percent factor IX in the blood. In such individuals, the healthcare provider can suspect Christmas disease if there is:

• Spontaneous internal bleeding as evident from blood in urine and feces.
• Bleeding in joints and muscles which causes swelling and pain
• Prolonged nosebleeds
• Prolonged bleeding from minor cuts and trauma
• Prolonged bleeding during dental procedures, circumcision and vaccination

What are the treatment options?

Since this is an inherited disorder, there is no cure for the disease. However, regular treatment can help to manage the symptoms of the disorder. These include:

• Factor IX injections: administration of exogenous factor IX can help to prevent and even stop the bleeding. This factor is separated from either donated human blood or manufactured in the laboratory. The latter is referred to as recombinant factor IX. 
• Preventive transfusions can also be performed by Hematologist in Karachi.