Investigation of a novel PROS1 splicing variant in a patient with protein S deficiency.

Here, we report a novel PROS1 splicing mutation in a patient with type I protein S deficiency. Qualitative and quantitative analysis of pathogenic splicing variants at the mRNA level was performed by long-range PCR-based targeted DNA and RNA sequencing. A base substitution in the exon 4 splicing donor site activates a potential splicing donor site in intron 4, resulting in an in-frame insertion of 48 bases (16 amino acids).