Liver function tests may be abnormal before the onset of seizures

EEG shows slow activity with high amplitude, mixed with low amplitude high frequency polyspikes

VEP are absent, asymmetrical, or with an ill defined initial component, with a normal electroretinogram²

There is progressive cerebral atrophy on cranial imaging, most marked in the occipital region

Liver pathology shows severe microvesicular fatty change, diffuse bile duct proliferation, bridging fibrosis, a disorganised hepatic architecture, with ongoing hepatocyte necrosis

Macroscopic brain pathology shows a variably distributed thinned, granular, and discoloured cortical ribbon, typically involving the calcarine cortex

Brain pathology typically affects the striate and occipital cortex and ranges from a mild superficial astrocytosis, through an increasingly deep sponginess, nerve cell loss and gliosis, to a thin and disorganised cortical ribbon, with hypertrophic astrocytes replacing nerve cells and a prominent vascular component

Atypical forms exist, with a fulminant course with seizures predominating, a prolonged survival, or late presentations,⁹ sometimes with an axonal neuropathy¹⁵