PDE8B and Autosomal dominant striatal neurodegeneration: Heterozygous variants in PDE8B have been shown to underlie autosomal dominant striatal degeneration (ADSD),8, 9, 10 a rare genetic disorder marked by slowly progressive dysarthria, brisk deep tendon reflexes, and mild parkinsonism without tremor, along with a poor response to L‐dopa treatment.