Abnormal glomerular basement membrane morphology Glomerular basement membrane wrinkling 2020-11-28T21:18:45Z Irregular folding of the glomerular basement membrane with an intact lamina densa. Wrinkling and folding of the glomerular basement membrane (GBM) without glomerular epithelial cell hypertrophy and hyperplasia (formerly known an ischemic type of collapse). The urinary space is patent. The wrinkling is generally made by small regular infoldings of the GBM.