Regarding the pathogenicity of the variants depending on the gene involved, there were 5 PV, 5 LPV, and 2 VUS in the COL4A3 group, 7 PV, 1 LPV, and 4 VUS in the COL4A4 group, and 10 PV and 2 LPV in the COL4A5 group. Here, COL4A3 is linked to acquired polycythemia vera.