Auditory function associated with Col11a1 haploinsufficiency in chondrodysplasia (cho) mice

Heterozygosity for mutations in the fibrillar collagen gene COL11A1 causes sensorineural hearing loss in patients with Stickler syndrome or Marshall syndrome. Chondrodysplasia (cho) is a functional null allele of Col11a1 that causes lethal chondrodysplasia in cho/cho newborn mice, and osteoarthritis in cho/+ heterozygotes. To determine if Col11a1 haploinsufficiency causes hearing loss in cho/+ mice, auditory brainstem response (ABR) thresholds were measured at 2, 4, 6, 8 and 10 months of age. There was no difference in ABR thresholds for click and tone burst stimuli between cho/+ and +/+ mice at all ages. In contrast to the conclusion of a previous report, our results indicate that Col11a1 haploinsufficiency does not cause significant hearing loss on the C57BL/6 strain background. We conclude that Stickler syndrome and Marshall syndrome mutations in COL11A1 cause hearing loss via dominant negative effects upon wild-type fibrillar collagen polypeptides in the extracellular matrices of the cochlea.