NOTCH3 and snowflake vitreoretinal degeneration: It is caused by mutations in the NOTCH3 gene and results in aggregation of NOTCH3 extracellular domain in granular osmiophilic material (GOM) within blood vessel walls, degeneration of vascular smooth muscle cells (VSMCs) and a small vessel disease (SVD) type dementia [1, 2, 4].