CYP17A1 and hypertensive disorder: Therefore, we hypothesize that the measurement of blood flow using our system in zebrafish larvae, performed 3 days post-fertilization, may not represent the entirety of the effects of this gene, as sex determination and differentiation (which are vital to the role of cyp17a1 deficiency in human hypertension) only take place at 21–23 days post-fertilization in zebrafish (35).