Neonatal onset of congenital factor X deficiency : a description of two novel mutations with 6-year follow-up

Factor X congenital deficiency is a rare coagulation disorder involving autosomal recessive transmission. The clinical situation depends on the extent of the defect and may appear at any age. We report a case of a term newborn who developed a life-threatening bleeding event on the first day of life because of a Factor X (FX) deficiency. Fresh frozen plasma and FX intravenous replacement therapy were administered with normalization of the coagulation test. Genetic analysis identified two novel mutations (c.517G>T; c.139delG) in heterozygous state in the proband that were confirmed in the parents. We also describe a 6-year followup during which the patient has been administered prophylactic replacement therapy. The description of these two novel mutations and the long clinical follow-up help to increase our knowledge of the genotype-phenotype correlation of congenital FX deficiency, and provide information on better ways of managing the replacement therapy in patients with similar mutations.