To analyze the clinical phenotype and genetic testing results of a patient with inherit factor Ⅻ (FⅫ) deficiency, and to explore the clinical and molecular biological characteristics of FⅫ deficiency in the Chinese population.

Clinical case data were collected from proband with inherit FⅫ deficiency, and coagulation function-related laboratory tests and gene analysis were performed on family members. Additionally, literature searches were conducted in the China National Knowledge Infrastructure (CNKI) database, Wanfang Data Knowledge Service Platform, and PubMed database for relevant Chinese and English literature on FⅫ deficiency in the Chinese population, with the search period up to September 30th, 2023. The findings summarized the clinical manifestations, laboratory characteristics, and gene mutation features of FⅫ deficiency patients in the Chinese population.

The proband was a 37-year-old female parturient, with prenatal examination results indicating an activated partial thromboplastin time (APTT) exceeding 120 s, and factor Ⅻ activity (FⅫ:C) and antigen levels (FⅫ:Ag) both at 1%. The proband showed no history of clinical bleeding or thrombosis before pregnancy, and there was no excessive bleeding during the process of cesarean section surgery or the perioperative period. Gene sequencing revealed F12 gene compound heterozygous mutations, c.303_304del:p.His101Glnfs36 and c.1092dupC:p.Lys365Glnfs69. The proband's father, mother, brother, eldest daughter, second daughter, and son were all carriers of one heterozygous mutation, with varying degrees of reduction in FⅫ:C and FⅫ:Ag. A literature review identified 46 Chinese or English articles reporting a total of 87 cases of FⅫ deficiency in the Chinese population. There were no apparent clinical bleeding or thrombotic tendencies in terms of clinical manifestations. Among all patients, 42 F12 gene mutations were reported, with missense mutations being the most common (n=23, 52.4%). The catalytic (Peptidase S) domain was the most frequently affected structural domain (n=23, 52.4%). The most frequently detected mutation was c.1681G>A:p.Gly561Ser (n=16 cases, 19.3%), followed by c.1561G>A:p.Glu521Lys (n=12, 14.3%).

This study reports a case of inherit F Ⅻ deficiency with compound heterozygous mutations in the F12 gene, along with familial characteristics. The study summarizes the clinical features and analysis molecular biological characteristics of F12 gene mutations in the Chinese inherit FⅫ deficiency population, and provide a foundation for future systematic research.