CASE REPORTSGene variants in four pedigrees with hereditary coagulation factor XI deficiency and one novel mutation identificationLin, Fena,*; Weng, Miao-Shanb,*; Wu, Jiao-Renb; Fang, Sen-Haic; Yang, Li-YeaAuthor Information aCentral Laboratory bClinical Laboratory, Chaozhou Central Hospital Affiliated to Southern Medical University, Chaozhou cSanitation Clinical Laboratory, Center for Disease Control and Prevention of Shantou, Shantou, China Correspondence to Dr Li-Ye Yang, Central Laboratory, Chaozhou Central Hospital Affiliated to Southern Medical University, Chaozhou 521021, Guangdong Province, China E-mail: email@example.com Received 18 June, 2019 Revised 29 August, 2019 Accepted 26 September, 2019 Blood Coagulation & Fibrinolysis: March 2020 - Volume 31 - Issue 2 - p 160-164 doi: 10.1097/MBC.0000000000000861 Buy Metrics Abstract Coagulation factor XI (FXI) deficiency is a bleeding disorder with unpredictable severity. Patients with this condition usually suffer bleeding manifestations after trauma or surgery and are poorly correlated with plasma FXI activity (FXI:C). In the current study, we examined and identified the phenotype and genotype in four unrelated probands and their 32 relatives with hereditary FXI deficiency. The probands with severely reduced FXI:C but bleeding symptoms were only found in two probands. Mutation analysis showed that all the probands were FXI homozygous mutation or compound heterozygous mutation. Five mutations were identified including three nonsense mutations c.841C>T (p.Gln263X), c.1107C>A (p.Tyr351X) and c.1033A>T (p.Lys327X), respectively, one frameshift mutation c.1325delT (p.Leu424CysfsX8), and one splicing mutation c.326-1G>A. c.1033A>T (p. Lys327X), a novel mutation which lead to a premature stop codon at amino acid position 327, it may have an influence on protein characteristics and cause the corresponding disease. Copyright © 2020 YEAR Wolters Kluwer Health, Inc. All rights reserved.