This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urinary tract, Subject name: Pathology
Which of the following conditions are associated with pauci-immune crescentic glomerulonephritis- 
Select and explain. 
A. Henoch-schonlein nephritis, B. Lupus nephritis, C. Microscopic polyangitis, D. Alpo's syndrome
C: Microscopic polyangitis
Answer: C: Microscopic polyangitis 
Explanation: Pauci-immune type crescentic GN is defined by the lack of anti-GBM antibodies or significant immune complex deposition. Anti-neutrophil cytoplasmic antibodies (ANCA) typically are found in the serum, which, have a pathogenic role in some vasculitides. In some instances, therefore, crescentic GN is a component of systemic vasculitis such as microscopic polyangiitis or granulomatosis with polyangiitis. Ref: ROBBINS BASIC PATHOLOGY 10th ed Pg no: 563