The protein interaction models build reference to the human disease complex of hereditary spastic paraplegias (HSPs) and possibly Parkinson's disease (Jaberi et al., 2016), rather than to multiple sclerosis, in addition to primary torsion dystonia by interaction to GNAL (Fuchs et al., 2013) and to severe hypotonia by GNB1 (Petrovski et al., 2016). The gene discussed is GNB1; the disease is hereditary spastic paraplegia.