The HDL2c levels were negatively correlated with the systolic blood pressure (r = − 0.470, p = 0.031, n = 21), Phe plasma concentrations (r = − 0.484, p = 0.026) and MDA (r = − 0.580, p = 0.004) and positively with SAA (r = 0.517, p = 0.014, n = 22) in PKU patients. This evidence concerns the gene SAA1 and phenylketonuria.