SLC7A5 and phenylketonuria: Further analysis of blood phenylalanine dynamics in the entire subgroup of carriers of the LAT1 variant with PKU revealed a moderately positive correlation of BMI Z-scores at one year and of blood phenylalanine variability during the assessed period, which was represented by the SD of all recorded blood phenylalanine results in a given patient (r(52) = 0.42, p = 0.002).