Clinical characteristics and genetic analysis of a combined inherited antithrombin and factor Ⅶ deficiency pedigree / 中华检验医学杂志

ABSTRACT

Objective:To study the clinical characteristics and gene mutations in a family with combined inherited antithrombin (AT) and factor Ⅶ (FⅦ) deficiency, and explore the relationship between AT gene, F7 gene mutations and diseases. Methods:Pedigree investigation. Blood samplesand clinical dataswere collected fromthe proband and her family members (a total of 16 people in 3 generations) who admitted to the First Affiliated Hospital of Wenzhou Medical University in November 2018. The prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB), antithrombin activity (AT A), antithrombin antigen (AT Ag), protein C activity (PC A), protein S activity (PS A), FⅦ activity (FⅦ C), FⅦ antigen (FⅦ Ag) and other indicators were detectedto confirm the diagnosis. DNA direct sequencing analysis of all exons, flanking sequences, 5′ and 3′ untranslated regions of AT genes and F7 genes, and the mutation sites were confirmed by clone sequencingor reverse sequencing. Results:The AT A and AT Ag of the proband were 46% and 135 mg/L, respectively (reference range 250-360 mg/L), some of her family members′ s (father, aunt, two cousins, younger brother and nephew) AT A and AT Ag were reduced to 50% of normal range. Her father (Ⅰ 2), aunt (Ⅰ 4), elder brother (Ⅱ 7), younger brother (Ⅱ 8), and nephew (Ⅲ 3)′s FⅦ C were 45%, 50%, 48%, 47% and 48%, respectively; and their FⅦAg was within the normal range. Genetic analysis revealed that the proband(Ⅱ 6) and some of her family members (father, aunt, two cousins, younger brother and nephew) took rs3138521 polymorphism in the 5′ untranslated region of AT gene. Her father (Ⅰ 2), aunt (Ⅰ 4), elder brother (Ⅱ 7), younger brother (Ⅱ 8), nephew (Ⅲ 3) took c.1091G>A heterozygous missense mutationin exon 8 of F7 gene, resulting in p.Arg304Gln. Conclusion:The rs3138521 in AT gene and c.1091G>A in F7 gene, which may be the molecular mechanism leading to combined inherited AT and FⅦ deficiency in this family.