Small vessel diseases are conditions characterized by the narrowing of small arteries leading to an imbalance of blood supply upon demand. This results in a progressive chronic hypoperfusion with detrimental outcomes for the affected organ system and for the patient. Recent advances in genetic evaluation have identified several genetic variants causing cerebrovascular small vessel diseases. These diseases have common clinical presentation including recurrent strokes, progressive white matter degeneration, and debilitating dementia. The link between these pathologies is defects in the tunica media of arteries, which is composed mainly of vascular smooth muscle cells (vSMCs).