Although G6PD deficiency, which can cause problems in red blood cells upon certain triggers, is the most common human enzyme defect, affecting over 400 million people, including over 1 in 10 Black Blister Cell in G6PD Deficiency , Red Blood Cell with a clear vacuole like area on its membrane, resembling a blister., It usually results when splenic macrophages remove precipitated Heinz Frontiers Glucose 6 Phosphate Dehydrogenase Deficiency and Neonatal Hyperbilirubinemia: Insights on Pathophysiology, Diagnosis, and Gene Variants in Disease Heterogeneity Glucose 6 phosphate Dehydrogenase deficiency (G6PD deficiency) Labpedia.net Full article: G6PD Deficiency: Imbalance Of Functional Dichotomy Contributing to the Severity of COVID 19