Molecular characterization of factor X deficiency associated with borderline plasma factor X level

Abstract

Borderline plasma factor X (FX) levels might complicate the diagnosis of FX deficiency. An asymptomatic individual with 73% FX activity was identified to be heterozygous for the Val342Ala mutation. Expression studies suggested that this substitution is responsible for a CRM+ FX variant with normal activation but modestly reduced catalytic function.