Despite a large number of genomic studies searching for possible genetic causes of Parkinson’s disease, the literature consistently shows that environment plays a more important role than genes
Despite a large number of genomic studies searching for possible genetic causes of Parkinson’s disease, the literature consistently shows that environment plays a more important role than genes. For example, in a 2019 twin study that followed subjects till death, the heritability for Parkinson’s Disease was quite low (27% overall, and only 19% in pairs diagnosed over the age of 50). Further the concordance for Parkinson’s was 20% in identical twins and 13% in fraternal twins, which is unusually similar for a disease unless there are shared effects of early childhood environment. If we are to better prevent or treat Parkinson’s Disease we have to understand it’s causes- which are primarily environmental.
The challenge
Understanding the role of early life Parkinson’s is challenging because the disease onset is typically after the 6th decade of life, which means that researchers need to reconstruct environmental exposures that occurred in the 1950’s when conducting research on patients. While starting a contemporary study might address this issue, the disease onset would not begin until roughly the year 2080, long after the researcher has retired or passed away. If there were a way to reconstruct objectively the environment a patient experienced 60 years in the past, we may be able to unlock the causes of this neurodegenerative disease.
The solution: looking back decades into the past
The Mount Sinai Institute for Exposomics is a cutting edge program dedicated to measuring and understanding all the health relevant environmental exposures across the life span- i.e the “exposome.” Led by Dr Manish Arora, our researchers have developed such a technology to look back decades into the past, even as early as birth. In a recent study, we applied this to Lou Gehrig’s disease (also known as amyotrophic lateral sclerosis) – a neurodegenerative disease, that similar to Parkinson’s, impacts people older than 50 years. We discovered clear environmental and metabolic signatures linked to disease risk that were apparent from birth to 15 years of age. The full-text of the two papers can be found here:
https://journals.plos.org/ploscompbiol/article/comments?id=10.1371/journal.pcbi.1007773