Clinical Presentation of HemophiliaHemophilia are divided into severe, moderate and mild diseases depending on the level of functional factor VIII or factor IX. (normal levels are between 50% and 150%)
Mild hemophilia patients (factor levels >5% and <50%) bleed only after injury, invasive procedure or surgery. Carriers of hemophilia are also sometimes found to have factor levels in the Mild range.
Moderate hemophiliacs (factor levels - 2to5%) experience more bleeds, about once a month, usually after trauma, surgery or extreme exertion. They usually bleed in the muscles and joints. Once a bleeding occurs in a particular area, these patients may continue to have bleeding episodes in those areas.
Severe hemophiliacs (factor level<1%) bleed spontaneously usually in joints, muscles and soft tissues.
Joint and muscle bleeding may cause pain, tingling, heat, swelling, limited range of motion, etc. It commonly occurs in the ankles, elbows and knees but can also affect any joint in the body.
Rarely, bleeding can occur in mucous membranes such as the mouth, tongue, throat, nose, etc. Hematuria may also occur. Central nervous system bleeds such as intracranial or spinal cord bleeds are life-threatening and may present as stiff neck or back, headache, vomiting, confusion, change in behavior, slurred speech, focal deficits or unequal pupils. Other sites where major bleeds may occur is neck, throat, eye, GI system, hip, testes, retroperitoneum and following severe injury.
Hemophilia InheritanceThere are two types of hemophilia - Hemophilia A and Hemophilia B. Hemophilia A results from deficiency or abnormality of factor VIII. Hemophilia B results from deficiency or abnormality of factor IX. Both are inherited as sex-linked recessive disorder as the genes responsible for factor VIII & IX are located on the X chromosome. Females are usually carriers as they have two X-chromosome and can pass on the defective gene to her offspring. In a rare event, if the female inherits two defective genes, then clinical hemophilia may result. Female carriers of hemophilia may be symptomatic due to lower than normal clotting factor levels.
The following permutations-combinations can occur while inheriting hemophilia :-
Normal Mother + Father with hemophilia :
During each pregnancy, the female offspring has 100% chance of being a carrier and the male offspring is always normal. Hence, sons of hemophiliac fathers and normal mothers are normal.
Carrier Mother + Normal Father :
During each pregnancy, there is 25% chance of a normal female, 25% chance of a carrier female, 25% chance of a normal male and 25% chance of an affected male.
Carrier Mother + Father with hemophilia :
Each pregnancy has 25% chance of a female carrier, 25% chance a female with hemophilia, 25% chance of a normal male and 25% chance of an affected male.
Mother with hemophilia + Father with hemophilia :
During each pregnancy, there is 50% chance of an affected female and a 50% chance of an affected male (actual occurrence is rare).
Mother with Hemophilia + Normal Father :
During each pregnancy there is 50% chance of a carrier female and a 50% chance of an affected male though the actual occurrence is rare.