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Hemophilia B in a female
1Institute of Immunohaematology, Indian Council of Medical Research, KEM Hospital, Parel, Mumbai, India.
Acta Haematologica
|November 20, 2001
Summary
This report details a rare case of severe hemophilia B in a female with a normal 46,XX karyotype. Genetic analysis suggests a homozygous or double-heterozygous mutation in the factor IX gene.
Area of Science:
- Genetics
- Hematology
- Pediatrics
Background:
- Hemophilia B is a rare X-linked recessive bleeding disorder, typically affecting males.
- Female hemophilia B is exceptionally rare, with few documented cases.
- This case presents a unique diagnostic challenge due to the patient's sex and karyotype.
Observation:
- A female patient presented with a severe clinical course of hemophilia B.
- She possessed a normal 46,XX karyotype without Turner's syndrome or dysmorphic features.
- Factor IX levels were moderately decreased (Factor IX:C, 1.5 U/dL; Factor IX:Ag, 2.2 U/dL).
Findings:
- The patient's father and paternal uncle also had factor IX deficiency.
- The mother exhibited intermediate factor IX levels (Factor IX:C, 46 U/dL; Factor IX:Ag, 39 U/dL), suggesting carrier status.
- DNA analysis revealed a unique factor IX gene allele in the mother, consistent with a homozygous or double-heterozygous state in the affected daughter.
Implications:
- This case expands the understanding of genetic mechanisms underlying hemophilia B in females.
- It highlights the importance of comprehensive genetic evaluation in atypical presentations of bleeding disorders.
- The findings may inform genetic counseling and diagnostic approaches for families with hemophilia B.