Parkinson’s disease is understood to start when dopamine-releasing nerve cells lose function. In a recent study led by researchers in the United States, scientists found that this degradation is preceded by a breakdown in the connections between neurons. The team notes that addressing the disease at this early stage could offer the greatest chance for effective treatment, as reported by the study authors.
Parkinson’s disease affects more than 10 million people worldwide and is marked by a gradual loss of dopamine-producing neurons. When these cells fail, movements become uncontrolled, stiffness sets in, balance falters, and tremors emerge. Scientists believe the loss of dopamine neurons stems in part from aging mitochondria in brain cells, organelles that supply energy for cellular processes.
Earlier research has shown that mutations in the Parkin and PINK1 genes raise the risk of Parkinson’s because these genes are central to mitochondrial upkeep. Everyone carries two copies of each gene, inherited from both parents. In the new study, researchers examined the neurons of two sisters who were born without the PINK1 gene while both parents carried only one copy. The findings from this case shed light on how these genetic changes influence disease onset and progression.
One sister received a Parkinson’s diagnosis at age 16, while the other sister lacked both PINK1 and Parkin genes. A third nuance appeared when the second sister exhibited a partial loss of Parkin yet still developed the disease at age 48. This outcome surprised researchers because partial Parkin loss is not typically linked to Parkinson’s, prompting deeper examination of the gene’s broader role.
Investigators discovered a previously unknown function for this segment of DNA. It turns out that this part of the genome is not only essential for managing mitochondrial quality but also plays a crucial role in releasing dopamine at synapses, the junctions where neurons communicate. The implications are profound: the complete absence of Parkin may disrupt connections between dopamine neurons from birth, potentially triggering an earlier disease onset in one sister, whereas partial Parkin exposure in the other appeared to preserve neuronal connections longer.
The results suggest that disruptions to dopamine neuron networks occur well before the actual loss of these cells. In other words, Parkinson’s disease may begin to form far earlier than scientists previously believed. The researchers propose that therapies targeting synaptic activity before neuronal deterioration starts could help prevent the onset of Parkinson’s symptoms in at-risk individuals.
These insights also imply that accelerating the drug development process could yield faster interventions. By focusing on synaptic mechanisms early in the disease timeline, researchers may shorten the path from discovery to effective treatments, potentially speeding up therapeutic options for patients in North America and beyond.
Note: The study contributes to a growing picture of how genetic factors and cellular aging intersect to shape Parkinson’s disease. It emphasizes the importance of looking beyond neuron death to understand the initial wiring and signaling changes that set the stage for symptoms later in life.