Table 1.

Comparison of phenotypes among mouse strains with different Slc26a4 variants.

	Slc26a4−/− [13]	Slc26a4loop/loop [14]	Tg[E];Tg[R];Slc26a4Δ/Δ [18]	Slc26a4919A>G/919A>G [15]	Slc26a4H723R/H723R [16]	Slc26a4 L236P [17]	hH723R Tg [19]	Slc26a4C565Y/C565Y
Audiological phenotypes	Profound hearing loss (>100 dB SPL)	Profound hearing loss (>100 dB SPL)	Hearing levels depend on the time of Slc26a4 expression. Doxycycline initiation at E18.5 (IE18.5) results in partial hearing loss	Profound hearing loss (>120 dB SPL)	Normal	Moderate-to-profound hearing loss in mice at 1 month. No progressive hearing loss up to 9 months	Profound hearing loss (>100 dB SPL)	Normal
Cochlear hair cells	Severe degeneration of inner and outer hair cells by P45	ND	Functionally intact at P25 to P35	Severe degeneration of inner and outer hair cells at 6 w	Normal up to P60	Different degrees of hair-cell degeneration and abnormal structures of stereocilia	Mild-to-severe degeneration of hair cells	Normal up to P90
Stria vascularis	Atrophic	ND	No significant difference between wild-type, IE18.5, and discontinued at E17.5 (DE17.5)	Atrophic	Normal	Atrophic	Atrophic	Normal
Vestibular aqueduct and enndolymphatic hydrops	Enlarged	ND	Size depends on time of Slc26a4 expression. Significantly enlarged in E18.5 mice	Enlarged	Normal	ND	Enlarged	Normal
Vestibular phenotypes	Vestibular deficits, including head tilting, head bobbing, and circling	Variable vestibular deficits, including unsteady gait, circling and tilted body	ND	46% of mice with head tilting and circling	Normal	9 of 31 L236P mice had balance dysfunction. Vestibular dysfunction variable in L236P mice	ND	Normal
Vestibular hair cells	Severe degeneration of vestibular hair cells by P45	Normal morphology of vestibular hair cells at 2 m	ND	Loss and degeneration of utricular hair cells	Normal	Normal	ND	Normal

ND, not described. Note: Slc26a4^loop/loop, mice homozygous for p.S408F mutation.