Disease 'X' is an inflammation of synovial membrane in synovial joints that occurs in younger people. It is the result of an auto-immune reaction. Disease 'X' is

Options

A. Still's disease
B. Gaucher's disease
C. osteoarthritis
D. Parkinson's disease

Answer

To solve the question regarding disease 'X', we need to analyze the characteristics provided in the question and match them with the options given.

### Step-by-Step Solution:

1. **Identify the Characteristics of Disease 'X':**
- Disease 'X' is described as an inflammation of the synovial membrane in synovial joints.
- It primarily affects younger people.
- It is a result of an autoimmune reaction.

2. **Evaluate the Options:**
- **Option 1: Stills Disease**
- This is known as systemic juvenile idiopathic arthritis. It is characterized by inflammation of the joints and is indeed an autoimmune disorder that primarily affects younger individuals.
- **Option 2: Gaucher's Disease**
- This is a genetic disorder that involves the accumulation of fatty substances in certain organs, leading to enlargement of the liver and spleen. It is not primarily an autoimmune disease or related to joint inflammation.
- **Option 3: Osteoarthritis**
- This is a degenerative joint disease that typically occurs due to wear and tear of cartilage and is more common in older adults, not primarily an autoimmune disease.
- **Option 4: Parkinson's Disease**
- This is a neurodegenerative disorder affecting movement and is not related to synovial joint inflammation or autoimmune reactions.

3. **Conclusion:**
- Based on the characteristics of disease 'X' and the evaluation of the options, the correct answer is **Stills Disease**, as it matches all the criteria provided in the question.

### Final Answer:
Disease 'X' is **Stills Disease**.