Variant rs398122403 was found to disrupt the phosphatase activity of Sac domain on SYNJ1 protein, leading to an impaired synaptic function of SYNJ1 and causing an accumulation of endocytic proteins in the brains of mutant mice, developing neurological symptoms similar to PD patients (Cao et al., 2017). The gene discussed is SYNJ1; the disease is Parkinson disease.