There is bilateral increased T2/FLAIR signal in the periventricular white matter, most prominent in the parietal regions. There is also mild corresponding diffusion restriction.
No cerebral atrophy, with age-appropriate ventricles and sulci. The cerebellum is normal. No abnormality of the corpus callosum, brainstem or other midline structures. No intracranial mass lesion.
Conclusion:
Periventricular high T2/FLAIR signal is consistent with phenylketonuria.