Cognitive impairment and McArdle disease: Is there a link?

McArdle disease is caused by deficiency of myophosphorylase, the muscle isoform of glycogen phosphorylase. This isoform is also expressed in astrocytes, where it seems to have a key role in neural energy metabolism. Whereas in other glycogen storage diseases cognitive impairment has been rarely reported, it has not been previously observed in McArdle disease. Here we report the case of an Italian 55-year-old woman with McArdle disease and cognitive impairment with bilateral dysfunction of prefrontal and frontal cortex (shown by neuropsychological assessment and fluorodeoxyglucose PET). Further studies are needed to assess the prevalence of central neurological manifestations in this disease.