This could link the genetic association found in the 5' MAPT locus for LOPD that seems to lead to enhanced tau expression [Kwok] [Skipper] with a functional consequence of impaired intraneuronal transport due to microtubule breakdown and altered tau expression (i.e. presynaptic accumulation of α-synuclein and mitochondrial breakdown, two classical features of PD). The gene discussed is MAPT; the disease is Parkinson disease.