AQP4 and oculocutaneous albinism type 1: The same evidence was demonstrated with chi-squared association test, when comparing the ATN groups with the AQP4-High and AQP4-Low group, defined as previously mentioned (AQP4-High: 23 N + , 27 N − ; AQP4-Low: 10 N + , 41 N − ; chi-squared test: χ2 = 7.99, p = 0.005).