,21 We identified an Arab family with an unexplained form of young-onset parkinsonism, and, utilizing direct sequencing, homozygosity mapping, whole-exome sequencing, co-segregation analysis, and functional studies, we report a candidate variant ([GeneBank: NM_032291] c.2080T>G [p.W694G]) in the SGIP1 gene as the most plausible underlying cause of disease. The gene discussed is SGIP1; the disease is Parkinson disease.