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 these does not cause crescentic glomerulo nephritis - 
Select and explain. 
A. Rapidly progressive glomerulonephritis, B. Alpo syndrome, C. Goodpasture syndrome, D. Henoch schonlein purpura
B: Alpo syndrome
Answer: B: Alpo syndrome 
Explanation: There are some systemic diseases that are characterized by the formation of crescents. Systemic diseases such as Goodpasture's syndrome, SLE, Henoch-Schlein purpura come under type1 RPGN and they are associated with crescent formation. Alpo's syndrome is an x-linked dominant disorder and the light microscopy shows segmental proliferation of mesangial cells with increased mesangial matrix and occasional segmental sclerosis. Another prominent feature is the presence of lipid-laden foam cells in the interstitium. Ref: TEXTBOOK OF PATHOLOGY HARSH MOHAN 7th edition, pg no:654,655,665