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Combined hereditary deficiency of the sixth component of complement and factor VIII coagulant activity in a Dutch
Insights
Complement component 6 (C6) deficiency does not impact blood clotting in individuals with hemophilia A. This study found no clinical bleeding issues in patients with combined C6 and factor VIII deficiency.
Area of Science:
- Hematology
- Immunology
- Genetics
Background:
- Previous studies noted defective blood clotting in C6-deficient rabbits.
- A patient with combined C6 and factor VIII deficiency prompted this investigation into hemostatic functions.
Observation:
- Three family members were homozygous for C6 deficiency (C6D), with two also deficient in factor VIII.
- One member was deficient only in factor VIII.
- The C6D member without hemophilia A exhibited normal recalcification time and no bleeding symptoms.
Findings:
- Reconstituting plasma from affected family members with purified human C6 did not alter recalcification times.
- The study indicates no genetic linkage between the inheritance of C6 and factor VIII.
Implications:
- C6 deficiency alone does not appear to cause significant hemostatic defects or bleeding disorders.
- Understanding these deficiencies aids in diagnosing and managing coagulation disorders.
Abstract:
Prompted by previous observations of defective blood clotting in rabbits deficient in the sixth component of complement (C6), and the discovery of a patient with both C6 and factor VIII deficiency, an evaluation was made of the haemostatic functions in this individual and his family members. The family contained three members homozygous for C6 deficiency (C6D); two of them were deficient also in factor VIII. In addition, one other member of the family was only deficient in factor VIII. The only C6D member without haemophilia A had a normal recalcification time without clinical symptoms of a bleeding disorder. Reconstitution of factor VIII and C6 deficient plasma from the various members of the family in this study with purified human C6 did not result in a change in the recalcification time. The results obtained from this study also indicate that there is no linkage between the inheritance of C6 and factor VIII.