Intriguingly, the delineation of the phenotypic spectrum associated with genetic defects of JPH3, including triplet expansions or (disruptive) intragenic variants, reveal a broad phenotypic spectrum including early developmental delay and (paroxysmal) dystonia as well as late cognitive impairment (often progressing to dementia) and different hyperkinetic movements. The gene discussed is JPH3; the disease is Global developmental delay.