C4A and Renal atrophy: A new renal biopsy revealed the progression of FSGS up to 40% of glomeruli, with renal atrophy, interstitial fibrosis associated with severe interstitial infiltrate, and glomerular deposits with segmentary distribution of IgM (3/4), C3, C4, C1q (2/4), and arteriolar deposits of C3.