Ever wondered why some people inherit Parkinson’s disease while others don’t? Let’s explore the genetic puzzle and uncover the answers.
Parkinson’s disease is a progressive brain disorder that affects over 10 million people worldwide. Its most common symptoms include slow movement, stiffness, tremors, and problems with balance. These symptoms occur when the brain loses its ability to produce a sufficient amount of dopamine, a neurotransmitter that regulates coordinated body movements.
The current data reveals that the lifetime risk of developing Parkinson’s in the general population is approximately 2%. However, for children of parents with Parkinson’s, the risk rises, though not dramatically. Children of Parkinson’s patients face a 4% risk, merely double the baseline. In simpler terms, it signifies that most children born to parents with Parkinson’s will not inherit the disease.
However, for a small percentage of Parkinson’s cases, genetics does play a significant role. Around 5% of Parkinson’s disease cases can be traced back to inherited gene abnormalities or mutations. In families where multiple members are affected by Parkinson’s, the risk can be as high as 50% for the children of an affected person. This is where genetic counseling and testing can come into play.
What genes are linked to Parkinson’s disease?
Researchers have uncovered numerous genes linked to Parkinson’s disease. Each gene plays a unique role in this complex neurological condition. Some of these genes directly cause the disease, while others act as genetic “risk factors,” increasing the likelihood of developing Parkinson’s disease.
Here’s a list of the most common genes linked to Parkinson’s disease.
SNCA: The SNCA gene plays a pivotal role, producing a small protein called alpha-synuclein primarily found in the brain. Mutations in SNCA lead to the formation of abnormal structures within neurons known as Lewy bodies, a hallmark of Parkinson’s disease. Depending on the specific mutation, it can either cause the disease or increase the risk of developing it. SNCA mutations are responsible for only a small fraction of Parkinson’s cases in the general population, typically affecting individuals under the age of 50.
PINK1: The PINK1 gene encodes the PINK1 protein, a significant player in the genetic form of Parkinson’s disease. Its critical role is to safeguard mitochondrial function within the cell, especially during periods of stress. Researchers have identified more than 70 different mutations in the PINK1 gene linked to Parkinson’s disease. Individuals carrying these mutations typically begin experiencing symptoms in their 40s or later.
PARKIN: PARKIN was the pioneer among the genes linked to the familial form of Parkinson’s disease. It codes for a protein named Parkin, which collaborates with the aforementioned PINK1 to remove damaged mitochondria from the cell. Numerous mutations have been pinpointed within the PARKIN gene, all recognized as culprits behind Parkinson’s disease. These mutations are responsible for the majority of cases involving early-onset Parkinson’s disease.
PARK7: The PARK7 gene serves as a blueprint for creating the DJ-1 protein, a vital player in the cell’s antioxidant defense system. Much like other Parkinson ’s-related genes, mutations within PARK7 are linked to early-onset Parkinson’s disease. Most individuals with mutations in this gene begin experiencing Parkinson’s symptoms around the age of 50 or even earlier.
ATP13A2: ATP13A2 is a relatively recent addition to the realm of Parkinson’s disease genetics. It provides instructions for making a protein called ATPase Cation Transporting 13A2. Mutations within the ATP13A2 gene lead to a rare subtype of Parkinson’s disease referred to as Kufor-Rakeb syndrome, named after the Jordanian district where it was initially identified. This condition tends to affect individuals at a young age, with the youngest known patient being a 12-year-old boy from Lithuania.
LRRK2: Much like SNCA, LRRK2 has a dual role. In some cases, it acts as a causative gene, while in others, it increases the risk of developing Parkinson’s disease. The LRRK2 gene encodes a protein called leucine-rich repeat kinase 2 (LRRK2), also known as dardarin. The clinical symptoms of LRRK2-related Parkinson’s resemble those of typical Parkinson’s disease and typically manifest after the age of 50.
GBA: The GBA gene provides instructions for making an enzyme called beta-glucocerebrosidase. Defects in this gene are known to cause Gaucher disease, a rare genetic disorder affecting many of the body’s organs and tissues. Typical symptoms of Gaucher disease include bone pain, anemia, enlarged organs, a swollen and painful belly, and bruising.
Remarkably, some patients with Gaucher disease also develop symptoms akin to Parkinson’s disease, such as tremors and mobility issues. This observation has led scientists to consider that even if you have just one altered copy of the GBA gene, you might still be at risk for Parkinson’s disease.
In conclusion, if you are the child of someone with Parkinson’s disease, your risk of inheriting it is only 4%, indicating no immediate need for specific lifestyle changes or preventive therapies. Nevertheless, genetic testing can provide valuable insights if available and advisable.
The genetics of Parkinson’s is like a challenging puzzle. These genes are just one part of the bigger Parkinson’s story. Ongoing research keeps making it clearer, giving us hope for better ways to diagnose and treat it in the future.
Disclaimer: The information shared here should not be taken as medical advice. The opinions presented here are not intended to treat any health conditions. For your specific medical problem, consult with your healthcare provider.