AHC is an ultra-rare epilepsy and neurodevelopmental disease. The prevalence is 1 in a million, and it was first reported in the medical literature in 1971. A groundbreaking discovery in 2012 highlighted that the ATP1A3 gene causes approximately 70-80% of cases. This gene codes for a sodium/potassium ion pump which is critical for the neurological system. AHC can present with any and every neurological symptom. It is like living with many different neurological diseases in one. This makes AHC both fascinating for clinicians and researchers and frightening for parents and carers. AHC is a life-long condition, despite its name suggesting a childhood disease. However, the first symptoms classically begin in childhood before the age of 18 months. There are about one hundred AHC-causing mutations discovered so far in the ATP1A3 gene, some more frequent than others. However, this genetic variation doesn’t fully explain the clinical variation in phenotype. Moreover, about 20% of AHC patients do not have a mutation in the ATP1A3 gene, leading many experts to believe there are more genes yet to be discovered to explain this rare epilepsy.
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