The mutants exhibit circling and head tossing behavior by weaning age (at 3-4 weeks), and three animals tested at four weeks of age for Auditory brain stem response were deaf. Mutants of either gender have been produced and the colony is maintained through regular breeding. Serial sections of the ears of two mutants (24 and 29 days of age) and additional whole ear histology on one mutant (33 days of age) revealed no abnormalities. Standard pathology work-up on all three animals showed no other abnormalities. Because of the map position of this mutation, and its phenotypic similarity to the waltzer mutations, a series of complementation tests has been performed to determine if allelic relationships exist between NMF181, NMF112, NMF252 and Cdh23. The results showed NMF181 to be an allele of NMF112(one mating produced 2 mutants in a total of 7 progeny), of NMF252(one mating produced 2 mutants in a total of 8 progeny) and therefore of Cdh23, since NMF252 has been identified as a new allele of Cdh23. This information suggests therefore that NMF181 mutants might be useful for studying neurobiological mechanisms related to Usher syndrome and human deafness.
Serial sections of the ears of two mutants (24 and 29 days of age) and additional whole ear histology on one mutant (33 days of age) revealed no abnormalities. Standard pathology work-up on all three animals showed no other abnormalities.
