SNP Shot: Genomic Insights

Parkinson's disease is a progressive neurological condition that primarily impacts the nervous system. It affects multiple brain areas, notably the substantia nigra, a region crucial for controlling movement and maintaining balance.

A common initial symptom of Parkinson's disease is an involuntary trembling or shaking (tremor), particularly in a limb when at rest. This tremor usually starts on one side of the body, often in a hand. Tremors can also affect the arms, legs, feet, and face. Other typical symptoms include muscle rigidity or stiffness in the limbs and torso, slowness of movement (bradykinesia) or difficulty initiating movement (akinesia), and problems with balance and coordination (postural instability). These symptoms gradually worsen over time.

Parkinson's disease can also impact emotional well-being and cognitive function. Some individuals with Parkinson's develop psychiatric conditions like depression and experience visual hallucinations. Furthermore, there is an elevated risk of developing dementia, a decline in cognitive abilities affecting judgment and memory.

Parkinson's disease that develops after the age of 50 is generally classified as late-onset. If the signs and symptoms appear before age 50, it's considered early-onset. In cases where the condition begins before age 20, it is sometimes referred to as juvenile-onset Parkinson's disease.

Inheritance:

The majority of Parkinson's disease cases occur in individuals with no known family history of the condition. These sporadic cases may not be inherited, or the inheritance pattern might be unclear. In familial Parkinson's disease, the inheritance pattern varies depending on the specific gene involved. When the LRRK2 or SNCA gene is affected, the disease follows an autosomal dominant inheritance pattern. This means that having just one copy of the altered gene in each cell is enough to cause the disorder. Typically, an affected individual has one parent who also has the condition. If the PARK7, PINK1, or PRKN gene is involved, Parkinson's disease is inherited in an autosomal recessive pattern. This means that both copies of the gene in each cell must carry a mutation for the disorder to develop. The parents of someone with an autosomal recessive condition each carry one copy of the mutated gene, but usually do not show any symptoms of the disease. When genetic variations influence the risk of developing Parkinson's disease, the specific inheritance pattern is usually not well-defined.