PINK1 and Parkinson disease: In a new study61, an analysis of a larger set of PRKN/PINK1 biallelic carrier PD patients and heterozygous PRKN/PINK1 carriers both with and without PD symptoms, mtDNA heteroplasmy along with major arc deletions and 7S DNA were identified as potential disease manifestation markers for PINK1/PRKN PD.