COL4A1 and snowflake vitreoretinal degeneration: Although unlikely because of absence of systemic signs or symptoms and familiar history, we didn’t perform genetic analysis to exclude hereditary diseases or heterozygous carriers status associated with sporadic SVD (e.g. CADASIL, CARASIL, MELAS, Fabry Disease, COL4A1/2 polymorphisms and other hereditary collagenopathies).