Furthermore, we identified a cytosine insertion in the VNTR region of MUC1 (on additional targeted testing), which has been associated with ADTKD-MUC1; however, our patient (F332) presented with a creatinine increase and FGGS in the kidney biopsy, which has been performed late in the disease course, i.e., 3 years before preemptive living kidney donation. Here, MUC1 is linked to autosomal dominant medullary cystic kidney disease with or without hyperuricemia.