Supplementary Material for: Contiguous Gene Deletion Involving COL4A1 and COL4A2 in a Patient with Thin Basement Membrane Nephropathy: A Case Report

Introduction: Type IV collagen trimers are major structural components of the kidney glomerulus and tubules. Several loss-of-function COL4A1 and COL4A2 variants have been reported to cause cerebral small vessel disease. However, there is little evidence to suggest that loss-of-function variants in these genes can cause kidney disease. Case Presentation: Here we report a case of a patient with thin basement membrane nephropathy and chronic kidney disease (CKD) who was found to bear a 1.9Mb heterozygous contiguous gene deletion of chromosome 13q33.3-q34 that includes COL4A1 and a large region of COL4A2. Conclusion: We propose that haploid expression of COL4A1 in combination with COL4A2 can lead to thin basement membrane nephropathy and CKD.