A phenotypic mutant that arose in an outbred ICR colony at the National Institute of Health (Japan) in 1986. This is the main causative gene producing nephrosis in the ICGN strain. An 8 base pair deletion in exon 18 (NM_001355636.1:c.1546_1553delTCATCCAC GRCm39:chr15:102019657-102019684delTCATCCAC) causes a frameshift and premature stop codon (p.S516Afs*19). Tenc1 expression is significantly decreased in all organs of ICGN animals.