PROS1 and congenital vertical talus: Whole Exome Sequencing (WES) was performed for five patients and revealed likely pathogenic mutations associated with CVT, including heterozygous PROC c.1218G > A (p. Met406Ile), heterozygous PROS1 c.301C > T (p. Arg101Cys), composite heterozygous mutation in the F8 gene (c.144-1259C > T; c.6724G > A (p. Val2242Met)) and homozygous MTHFR c.677C > T (p. Ala222Val).