PNPLA6 and spastic ataxia: There are a variety of PNPLA6 phenotypes with specific combinations of clinical features, such as spastic ataxia (spasticity & ataxia), Gordon Holmes syndrome (spasticity, primarily gait ataxia & hypogonadism), Boucher–Neuhäuser syndrome (ataxia, hypogonadism & chorioretinal dystrophy) and pure HSP (spasticity) [11].