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Headlines 5 The discovery of a gene variant that causes early-onset Parkinson’s disease in Pacific peoples will improve diagnoses and health services, and could shed light on the ancestry, customs and migration of people throughout the Pacific stretching back more than 1000 years. A single gene variant that causes early-onset Parkinson’s disease (EOPD) has been discovered in New Zealand’s Pasifika community, likely passed down from generation to generation for thousands of years. Researchers believe they can trace the variant back to the western Polynesian islands of Tonga and Samoa, perhaps to a single Pacific ancestor. Neurogenetic researcher Dr Christina Buchanan says the prevalence of the ‘PINK1 L347P’ gene variant was unexpected and is hugely significant. “Changes in the PINK1 gene are usually rare and multiple different variants are linked to only 4% of early-onset Parkinson's disease cases worldwide, which in turn is very rare,” Dr Buchanan says. In pilot DNA analyses of Pasifika and Māori Parkinson's disease patients in New Zealand, the L347P variant in PINK1 came up as the cause in all five of the people tested with EOPD (under the age of 50 years). “It really stood out. We went on and tested as many EOPD Pasifika and Māori patients that were referred to us and so far, 17 of 21 Pasifika EOPD patients are homozygous for the PINK1 gene variant, but the three Māori EOPD patients were PINK1 negative. We were astounded.” Being ‘homozygous’ means a patient has inherited two identical PINK1 gene variants, one each from their biological mother and biological father. While carriers don't get EOPD, if they partner with another carrier, their children are at a one-in-four risk of being homozygous. ”There is no word for Parkinson's or dementia in Pacific languages.“ Researchers are already aware that the specific PINK1 variant is carried by different populations in the Pacific. However, the high frequency in Western Polynesian people in New Zealand is a new discovery. The high carrier rates have also been found by collaborators in Samoa, who identified that the gene variant is carried at similar rates in a DNA store from people in its own health system. “Knowing there is a single gene change that causes 80% of EOPD cases in a population is a significant advantage when it comes to diagnoses and treatment,” says Dr Buchanan. Curiously, the gene variant does not commonly occur in Māori populations, which may reflect migratory patterns. Dr Buchanan has received funding from the Neurological Foundation to take the findings further, including collecting the experiences of Pacific people who carry the PINK1 gene. She has been joined by Dr Fuafiva Fa'alau, from the School of Population Health at the University of Auckland, who has a complementary interest in dementia in Pasifika communities. Dr Fa’alau is leading ‘talanoa’ sessions with PINK1 patients and their families alongside Dr Buchanan. Talanoa is a “My part is the narrative side, collecting their experiences and tracing their stories back to when they first felt symptoms...” Dr Fuafiva Fa'alau