Ames et al. (2022) compared the age of first IS in 82 adolescent patients with the TT genotype, 54 with the TC genotype, and 34 with the CC genotype of MTHFR, assessed MTHFR gene polymorphisms, and determined the predictors of the type of cerebrovascular involvement leading to IS (small‐vessel disease (SVD) versus large‐vessel disease (LVD)). The gene discussed is MTHFR; the disease is snowflake vitreoretinal degeneration.