Cerebellar atrophy without cerebellar cortex hyperintensity in infantile neuroaxonal dystrophy (INAD) due to PLA2G6 mutation.

Infantile neuroaxonal dystrophy (INAD) is a rare neurodegenerative disorder characterized by infantile onset and rapid progression of psychomotor regression and hypotonia evolving into spasticity. The neuroradiologic hallmark of the disease is represented by cerebellar atrophy and signal hyperintensity in the cerebellar cortex on MR T2-weighted images. We report a 2-year-old boy with psychomotor regression and hypotonia carrying a homozygous 5' splice site mutation in PLA2G6 gene, whose brain MRI revealed cerebellar atrophy with normal cerebellar cortex signal intensity. The absence of the signal hyperintensity of the cerebellar cortex does not rule out the diagnosis of INAD.