Haemophilia A occurs in one out of 5000 male births. Clinical signs emerge as the baby grows, especially when the baby starts to crawl and walk. A significant proportion of patients are diagnosed due to uncontrolled bleeding after circumcision. As the severity of haemophilia increases, the age of diagnosis shifts earlier and the clinical findings are more severe. For this reason, bleeding in patients with mild haemophilia usually occurs after serious traumas or surgical interventions, causing the diagnosis to be made at an older age.

The severity of bleeding symptoms correlates with the degree of the clotting factor deficiency. Patients with factor activity <1% show "severe haemophilia", those with 1-5% show "moderate haemophilia" and those with 5%-40% show "mild hemophilia". 

Haemophilia is a X-linked recessive hereditary disorder. The FVIII and IX genes are located on the long arm of the X chromosome (Xq27 and Xq28) and the disease is mostly inherited from female carriers to male children. Hemophilia can also be seen in females, although this is very rare.

References

1. Türk Hematoloji Derneği. Hemofili Tanı ve Tedavi Kılavuzu.Sürüm 1-Temmuz 2011. www.thd.org.tr [Accessed: June 2023]

2. WFH Guidelines for the Management of Hemophilia, 3rd edition Available at: https://onlinelibrary.wiley.com/doi/10.1111/hae [Accessed: June 2023]