This phenotypic mutant was identified in an ENU mutagenesis screen at the Baylor College of Medicine. It failed to complement the existing mutation Slc4a1tm1Llp. The mutation was identified as an A-to-T transversion resulting in a missense mutation in the codon corresponding to amino acid 541. This conserved glutamic acid within the fifth transmembrane domain is changed to a valine in the encoded protein. (J:85113)