Neurodegenerative Diseases

• 03 Jun 2025

Source: TH1, TH2 

Why in News? 

Recent research by National Centre for Biological Sciences (NCBS-TIFR) and other studies has revealed that neurodegenerative diseases may start long before symptoms appear, driven by blood vessel dysfunction and abnormal protein activity in the brain. 

• This new understanding moves the focus from direct neuron damage to early vascular and molecular changes, paving the way for earlier diagnosis and prevention. 

What are Neurodegenerative Diseases? 

• About: 
  • Neurodegenerative Diseases are a group of disorders in which the brain and nerve cells (neurons) gradually break down or die over time.  
    • This leads to problems with memory, movement, speech, and other important body functions. 
  • These diseases usually get worse over time and currently have no complete cure, though treatments can help manage symptoms. 
• Common Examples: 
  • Alzheimer's Disease, which affects memory and thinking. 
  • Parkinson’s Disease, which affects movement and balance. 
  • Amyotrophic Lateral Sclerosis (ALS), which affects nerve cells (motor neurons) in the brain and spinal cord, which control voluntary muscle movement. 
  • Huntington’s Disease, which causes nerve cells in the brain to decay over time 
  • Guillain-Barre syndrome, a serious autoimmune disorder that affects the peripheral nervous system.  

What does Recent Research Reveal about Early Causes of Neurodegenerative Diseases? 

• Vascular Dysfunction and Blood-Brain Barrier (BBB) Breakdown: The BBB is a protective layer formed by tightly connected cells lining brain blood vessels, regulating what enters the brain. Damage to this barrier, caused by dysfunction of the protein TDP-43, leads to leakage that allows harmful substances to enter, causing inflammation and neuron loss.  
  • Studies in mice show these vascular changes occur early, before symptoms, suggesting blood vessel damage is a key early factor in neurodegeneration. 
• Intracellular Membrane Signaling Failure (Esyt Protein Dysfunction): Neurons depend on membrane contact sites between the plasma membrane and endoplasmic reticulum for transferring essential molecules like lipids and calcium, crucial for cell signaling and survival.  
  • The Esyt protein regulates this process by binding calcium. When Esyt function is impaired, this signaling breaks down, disrupting neuron health and potentially initiating degeneration. 

What are the Key Factors Contributing to Neurodegenerative Diseases? 

• Genetic Factors: Mutations in specific genes disrupt normal neuronal function and repair, increasing susceptibility to degeneration. These mutations may be inherited or arise spontaneously. 
• Protein Abnormalities: Misfolded proteins, such as amyloid-beta in Alzheimer’s disease or alpha-synuclein in Parkinson’s disease, accumulate and interfere with cell function, triggering neuronal toxicity and progressive damage. 
• Oxidative Stress: Excess free radicals cause damage to neuronal DNA, proteins, and membranes. When antioxidant defenses are overwhelmed, this accelerates neuronal cell death. 
• Mitochondrial Dysfunction: Impaired mitochondria produce insufficient energy and release harmful byproducts, compromising neuron survival and promoting degeneration. 
• Chronic Inflammation: Persistent inflammation in the brain activates immune cells that can damage neurons, exacerbating disease progression. 
• Environmental Factors: Exposure to toxins like pesticides, heavy metals, or infections can induce cellular stress and damage, raising the risk of neurodegeneration. 
• Ageing: The natural ageing process weakens cellular repair and waste clearance systems, making neurons more vulnerable to damage and loss over time. 

Neurodegenerative Diseases V/s Neurological Disorders 

• Neurological disorders are a broader category of disorders affecting the nervous system, including the brain, spinal cord, and peripheral nerves and may be acute or chronic. 
  • Eg: Stroke, epilepsy, and meningitis.  
  • Many neurological conditions are treatable or reversible with timely intervention. Eg: Stroke (Ischemic Stroke). 
• Neurodegenerative diseases are a subset of neurological disorders characterized by the progressive and irreversible loss of structure or function of neurons, often due to abnormal protein accumulation, genetic factors, or oxidative stress.  
• They are largely incurable and managed symptomatically.

UPSC Civil Services Examination Previous Year Question 

Q. Consider the following statements:

1. Genetic changes can be introduced in the cells that produce eggs or sperms of a prospective parent. 
2. A person’s genome can be edited before birth at the early embryonic stage. 
3. Human induced pluripotent stem cells can be injected into the embryo of a pig. 

Which of the statements given above is/are correct? 

(a) 1 only  
(b) 2 and 3 only  
(c) 2 only 
(d) 1, 2 and 3 

Ans: (d)