POLG and progressive external ophthalmoplegia: Association of variants of POLG1 with parkinsonism was first reported in 2004, a study of seven families with POLG1-related progressive external ophthalmoplegia (PEO) revealed a co-segregation of parkinsonism with POLG1 variations, with the age of onset of parkinsonism varying between 36 and 75 years; post-mortem examination of two patients showed loss of pigmented dopaminergic neurons in the SNpc, but no presence of Lewy Body pathology [44].