Factor XIII Deficiency
The correct answer is C - Factor 13 deficiency. This presentation of delayed umbilical cord separation with bleeding from the site, combined with normal PT, PTT, platelet count and function, but prolonged bleeding time, is pathognomonic for Factor XIII deficiency.
Why Factor XIII Deficiency is the Answer
Factor XIII is uniquely responsible for cross-linking fibrin clots, and its deficiency presents with a characteristic clinical pattern that matches this case exactly:
Delayed umbilical cord separation is a hallmark finding - Factor XIII is essential for wound healing and tissue repair, and its deficiency classically causes the umbilical cord to separate late (often beyond 2-3 weeks) with persistent bleeding from the site 1, 2
Normal routine coagulation tests - Factor XIII deficiency does not prolong PT or PTT because these tests only measure clot formation up to the point of fibrin generation, not fibrin stabilization 1
Prolonged bleeding time with normal platelet function - The bleeding time can be prolonged because the clot formed is unstable and breaks down easily, even though platelet function itself is normal
Why the Other Options Are Incorrect
Factor VIII Deficiency (Hemophilia A)
- Would cause prolonged PTT, not normal PTT as described in this case
- Does not typically present with delayed umbilical cord separation
- Bleeding time would be normal
Von Willebrand Disease
- Would typically show prolonged PTT (due to low Factor VIII)
- Platelet function would be abnormal on specialized testing (ristocetin cofactor activity), contradicting the stated normal platelet function 3, 4
- While bleeding time may be prolonged, the combination with normal PT, PTT, and platelet function makes this diagnosis incompatible
Thrombocytopenia
- The question explicitly states platelet count is normal, eliminating this option entirely
- Would not cause delayed umbilical cord separation as a primary feature
Clinical Context and Pathophysiology
Factor XIII deficiency is a rare autosomal recessive disorder that affects approximately 1 in 2-5 million individuals. The enzyme is responsible for cross-linking fibrin polymers, creating a stable clot resistant to fibrinolysis.
Key Clinical Features Supporting This Diagnosis:
Umbilical cord bleeding - The umbilical stump requires robust wound healing and clot stabilization, making Factor XIII deficiency manifest early in life at this site 1, 2
Delayed separation timing - While normal cord separation occurs at 7-10 days in term infants, Factor XIII deficiency can delay this to 3+ weeks with ongoing bleeding 5
Normal screening tests - PT and PTT measure the extrinsic and intrinsic pathways only up to fibrin formation, not the subsequent cross-linking step that Factor XIII performs
Diagnostic Approach
To confirm Factor XIII deficiency:
- Factor XIII activity assay - This is the definitive test, measuring the enzyme's ability to cross-link fibrin
- Clot solubility test - A screening test where the patient's clot dissolves in 5M urea or 1% monochloroacetic acid (normal clots remain stable)
- Genetic testing - Can identify specific mutations in the F13A1 or F13B genes 2
Critical Management Considerations
Factor XIII deficiency carries significant morbidity and mortality risk if unrecognized:
- Intracranial hemorrhage occurs in 25-30% of untreated patients, often in infancy
- Prophylactic replacement therapy with Factor XIII concentrate or cryoprecipitate is essential
- Even minor trauma can cause life-threatening bleeding due to clot instability
- Wound healing is severely impaired, affecting surgical outcomes and spontaneous healing
This case represents a classic presentation that should trigger immediate Factor XIII testing and urgent hematology consultation.