A TCT to TAG change resulting in a threonine to methionine substitution at amino acid 58 (p.T58M) was introduced into exon 1. A loxP flanked neomycin selection cassette that was inserted downstream of exon 1 was removed via cre-expression in ES cells. This mutation corresponds to the p.T60M variant that is common in patients with Gitelman syndrome. (J:338297)