A point mutation in the adult beta globin gene (HBB) (c.20A>T, p.Glu7Val) results in the production of an abnormal hemoglobin (Hb S), which polymerizes when deoxygenated and leads to the classical clinical phenotype seen in sickle cell disease (SCD) [21]. The gene discussed is GSTM1; the disease is Schnyder corneal dystrophy.