Abstract
Introduction
Congenital factor X deficiency is one of rarest bleeding disorders, occurring in 1 out of 1 million births. Its rarity limits its consideration in newborns presenting with hemodynamic instability. It is autosomal recessive and seen frequently in the consanguineous population. Patients with factor X deficiency are classified into three groups, based on factor X activity level: severe (<1%), moderate (1%-4%), and mild (6%-10%). Severe deficiency presents with bleeding diathesis early in life.
Methods
A 3-day-old male newborn, delivered at term via spontaneous vaginal delivery, presented in a well-baby clinic for a routine bilirubin check. Family history was negative for bleeding disorder or consanguinity. Nurse noted persistent blood oozing at heel stick site and oral, nasal, and umbilical stump bleeding. The patient immediately developed respiratory distress and shock. Sepsis, vitamin K deficiency, and congenital metabolic syndrome were considered. Liver function, WBC count, and other chemistry were normal, and cultures were negative. Hemoglobin was low and platelet count was elevated. PT (30.3 seconds) and aPTT (53.3 seconds) were both prolonged. Mixing patient’s sample with normal plasma corrected PT (13.1 seconds) and aPTT (25.7 seconds), indicating a factor deficiency.
Results
Coagulation factor assays revealed normal levels of factors VII, VIII, IX, and II. Factor X activity (12.9%) was low. The patient’s condition improved after multiple pRBC and plasma transfusions. He was placed on a daily 25-mL/kg dose of fresh-frozen plasma, which maintained his PT at 17.6 to 19.1 seconds and aPTT at 34.1 to 48.0 seconds. Factor X level increased to 20% after plasma transfusion.
Conclusion
Congenital bleeding disorder should be considered for neonates presenting with bleeding and shock. Factor X deficiency is suspected when both PT and aPTT are prolonged and corrected with mixing studies. Although factor levels of 10% to 40% are considered adequate for hemostasis, our patient with 12% factor X activity presented with a life-threatening bleeding event.
Human coagulation factor X deficiency caused by a mutant signal peptide that blocks cleavage by signal peptidase but not targeting and translocation to the endoplasmic reticulum.