Wal Mutant Mice Have a Mutation Associated with Autism Spectrum Disorders

The waved alopecia (wal) mutation arose spontaneously in mice. Phenotypically, the wal mutation in a homozygous recessive state is manifested by a wavy coat. Over time, partial baldness develops, which leads to a thinning of the coat in mice. The molecular nature of the genetic defect in wal is still unknown; however, the coordinates of the chromosome locus in which the wal gene is located, a section of about 10⁷ bp in length, has been determined in mouse chromosome 14. We examined the wal locus by sequencing the exons of candidate genes in which the mutation was expected, and performed genome-wide sequencing to identify the cause of the wal mutation. The sequences of exons of candidate genes located in this region did not carry changes that could lead to a change in the structure of the protein. However, outside the wal zone, a mutation in the Slc9a9 gene was found that is probably not associated with the wal phenotype. According to the literature, a mutation in the Slc9a9 gene leads to autism spectrum disorders. This is the first discovered spontaneous mutation in the Slc9a9 gene in mice.