SH3PXD2A and snowflake vitreoretinal degeneration: Genome-wide association studies (GWAS) discovered several possible genetic factors that could contribute to sporadic form of SVD, such as NEURL1 (E3 ubiquitin protein ligase 1), PDCD11 (programmed cell death 11) and SH3PXD2A (SH3 and PX Domains 2A), which could be related to WMHs.