B4GALNT1 and Parkinson disease: Instead, the heterozygous mice (B4galnt1+/− mice), are characterized by a partial reduction of ganglioside GM1 and GD1a (GD1a is converted to GM1 by the membrane associated sialidase Neu3) with respect to the wild-type mice and present a mild manifestations of Parkinson’s disease better recapitulating the sporadic and progressive form of the disease [106,107,187,188,189]: α-synuclein elevation and aggregation within central and peripheral neuropathological lesions, nigro-striatal degeneration and worsening of motor dysfunction.