Haemophilia A and B: Statement Analysis

This question asks to identify the correct statements regarding Haemophilia A and Haemophilia B.

Statement Analysis

• Statement 1: are variants of the same disease process
  This statement is considered inaccurate in the context of specific classifications. While both are bleeding disorders affecting blood clotting, they are caused by deficiencies in different clotting factors (Factor VIII vs. Factor IX) and are classified as distinct genetic conditions.
• Statement 2: are due to congenital deficiency of factor VIII and factor IX respectively
  This statement is correct. Haemophilia A is caused by a deficiency in clotting Factor VIII, and Haemophilia B (Christmas disease) is caused by a deficiency in clotting Factor IX. Both are congenital conditions.
• Statement 3: both are sex linked characteristics and transmitted by asymptomatic females
  This statement is correct. Both Haemophilia A and B are X-linked recessive disorders. Males are primarily affected, while females often act as asymptomatic carriers, transmitting the condition to their offspring.
• Statement 4: can occur both in males and females
  This statement is technically true but potentially misleading as the primary inheritance pattern predominantly affects males. While females can be affected, it is much rarer than in males. Given the specific accuracy of statements 2 and 3, this statement is often considered less precise for exam purposes.

Conclusion

Based on the analysis, statements 2 and 3 provide the most accurate and defining characteristics of Haemophilia A and Haemophilia B.

Therefore, the correct combination is statements 2 and 3.