Although these levels were assessed in cultured lymphoblasts, the only tissue available to us for research in living subjects, our results provide indirect evidence for this marker’s relevance to neurological involvement in PM carriers by showing a significant (inverse) relationship of activated AMPK levels with the severity of tremor/ataxia (assessed by the ICARS), and some wmhs measures representing a degree of white matter pathology, across all three clinical categories of these carriers. The gene discussed is PRKAA1; the disease is cerebellar ataxia.