Identification of a novel mutation in the factor XIII A subunit in a patient with inherited factor XIII deficiency.

Inherited factor XIII (FXIII) deficiency is an extremely rare and under-diagnosed autosomal recessive inherited coagulopathy, which is caused by genetic defects in the F13A1 or F13B gene. More than 200 genetic mutations have been identified since the first case of inherited FXIII deficiency was reported. This study aimed to identify underlying gene mutations in a patient with inherited FXIII deficiency who presented with recurrent intracerebral hemorrhage. Levels of plasma FXIII-A antigen were measured, F13A1 and F13B genes were sequenced, mutation information was analyzed, and the mutated protein structure was predicted using bioinformatics methods. Molecular genetic analysis identified four mutations of FXIII-related genes in the proband, including three previously reported mutations inherited from his parents (c.631G>A, p.Gly210Arg and c.1687G>A, p.Gly562Arg of F13A1 gene and c.344G>A, p.Arg115His of F13B gene) and a novel spontaneous mutation of F13A1 gene (c.2063C>G, p.Ser687Cys). Molecular structural modeling demonstrated that the novel Ser687Cys mutation may cause changes in the spatial structure of FXIII-A and increase its instability. In conclusion, we identified a novel and likely pathogenic mutation of the F13A1 gene, which enriched the gene mutation spectrum of inherited FXIII deficiency. The findings may provide promising targets for diagnosis and treatment of inherited FXIII deficiency.