The child and her mother showed a low plasma concentration of fibrinogen measured by Von Clauss method, whereas a normal result measured by PT-derived method; finally, c.113G>C in the exon 2 of FGA was detected in the pedigree which caused Arg38Thr mutation and it is the first report on a pedigree with CD caused by AαArg38Thr. Here, FGA is linked to Cowden disease.