Voltage-gated potassium channel antibody-related encephalopathy: a case which may extend the documented phenotype of this condition.

A 51-year-old man presented with a focal epileptic, fluctuating encephalopathy. Antibodies to voltage-gated potassium channels (VGKC-Abs) were detected in his serum. Several features of this case were different from those previously reported in VGKC-Ab-associated encephalitis, illustrating that it may have a broader phenotype than previously documented. These features were: excess hepatic iron deposits without cirrhosis, reduced consciousness and fluctuating neurological signs. Previous history included personality change, depression, type 2 diabetes mellitus, pupil sparing third nerve palsy and epilepsy secondary to a head injury. He had never drunk alcohol and had recovered from a similar episode 4 years previously. Both episodes resolved after approximately 2 months. The cerebrospinal fluid had a raised protein content but no organisms. The patient was heterozygous for C282Y and negative for H63D mutations excluding classical idiopathic haemochromatosis. He recovered with supportive care to his premorbid level of health.