| Type | MGI:General | Description | at E15.5, homozygotes display variable inner ear phenotypes divided into four categories, with increasing severity from Type I to IV Type I homozygotes exhibit an enlarged membranous labyrinth which lacks the endolymphatic duct in 3/4 cases Type II homozygotes show absence of both the endolymphatic duct (7/7) and common crus (5/7); the utricle and saccule are not easily discernible, and the cochlear duct is shortened Type III homozygotes lack the anterior and posterior canals and show less than one coil, in addition to phenotypes described for Type II Type IV homozygotes display a cystic inner ear with only a lateral canal and ampulla in 3/5 cases in 8 of 10 cases, the two ears of a given specimen usually display similar phenotypes |
