Targeted disruption of angiotensinogen or renin gene caused anemia in 3-month-old male mice with a 30% reduced hematocrit level relative to the WT [Agt(-/-), 31.87 ± 1.61% (n = 13) and Ren(-/-), 31.86 ± 1.33% (n = 9); (both p < 0.0001, ANOVA followed by Tukey’s HSD post hoc comparisons) vs. WT, 44.46 ± 1.68% (n = 10)] (Fig 1A). The gene discussed is REN; the disease is anemia (phenotype).