Since some kidney diseases like congenital FSGS are associated with a down regulation of the slit diaphragm protein nephrin (17, 18), alternative slit diaphragm markers like podocin can be used as it was nicely demonstrated by Unnersjö-Jess et al. (3) in a STED-based work on optical cleared kidneys. This evidence concerns the gene NPHS2 and kidney disorder.