This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2019, Subject name: Anatomy
A lady when exposed to Cold, Extremities turn to blue. Which of the following antibody is associated with it? 
Select and explain. 
A. Anti SCL-70, B. Anti RO, C. Anti SS-A, D. Anti SS-B
A: Anti SCL-70
Answer: A: Anti SCL-70 
Explanation: The above scenario is described as Raynaud's phenomenon, which is seen in Scleroderma. Raynaud's phenomenon Fibrosis of skin around digital blood vessels On Cold exposure due to abnormal vasoconstriction Tip of fingers turns white. Antinuclear antibody (ANA) is the most sensitive antibody in scleroderma and is the preferred screening test. Anti-centromere antibody is most specific for CREST syndrome. Anti-topoisomerase I (Scl-70)is most specific fordiffuse systemic sclerosis/diffused Scleroderma.