Cochlear incomplete partition type III (IP-III) is the type of cochlear incomplete partition present in X-linked deafness, a rare, nonsyndromic, genetic cochlear anomaly associated with mixed conductive and sensorineural hearing loss.
The genetic disorder goes by many names 8:
- X-linked deafness type 2 (DFNX2)
- deafness type 3 (DFN3)
- conductive deafness with stapes fixation
- Nance deafness
- X-linked mixed conductive and sensorineural hearing loss
- X-linked progressive mixed deafness with perilymphatic gusher during stapes surgery
- X-linked stapes gusher 1
It is the most common cause of X-linked deafness.
It is caused by a mutation in the POU3F4 gene located on the X chromosome.
Male patients present with profound hearing loss (can be progressive) that is predominantly sensorineural +/- conductive. Female carriers have normal hearing or only mild hearing loss. Vestibular function is impaired in affected males, however normal in females.
- present interscalar septa
- absent modiolus
- absent cribriform plate (lamina cribrosa) between the basal turn of cochlea and internal auditory canal fundus
Additional findings are seen in X-linked deafness:
- internal auditory canal: bilateral and symmetrical widening of the fundus of the internal auditory canal (may be mild in female carriers)
- vestibular aqueduct: can be dilated
- vestibule and semicircular canals: can be slightly dilated with possible ossification of the semicircular canals
- facial nerve canal: dilatation of the labyrinthine and tympanic segments
Because of the abnormal communication between the subarachnoid and perilymphatic spaces, there is a high risk of gushing during stapes manipulation, and so recognition of the X-linked deformity is essential, precluding stapes surgery.
History and etymology
The term incomplete partition III was coined in 2006 by L Sennaroglu 6.
- 1. Kumar G, Castillo M, Buchman CA. X-linked stapes gusher: CT findings in one patient. AJNR Am J Neuroradiol. 2003;24 (6): 1130-2. AJNR Am J Neuroradiol (full text) - Pubmed citation
- 2. Altay H, Savaş R, OğüT F et-al. CT and MRI findings in X-linked progressive deafness. Diagn Interv Radiol. 2009;14 (3): 117-9. Pubmed citation
- 3. Phelps PD, Reardon W, Pembrey M et-al. X-linked deafness, stapes gushers and a distinctive defect of the inner ear. Neuroradiology. 1991;33 (4): 326-30. Pubmed citation
- 4. Papadaki E, Prassopoulos P, Bizakis J et-al. X-linked deafness with stapes gusher in females. Eur J Radiol. 1999;29 (1): 71-5. Pubmed citation
- 5. Incesulu A, Adapinar B, Kecik C. Cochlear implantation in cases with incomplete partition type III (X-linked anomaly). Eur Arch Otorhinolaryngol. 2008;265 (11): 1425-30. doi:10.1007/s00405-008-0614-z - Pubmed citation
- 6. Sennaroglu L, Sarac S, Ergin T. Surgical results of cochlear implantation in malformed cochlea. (2006) Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. 27 (5): 615-23. doi:10.1097/01.mao.0000224090.94882.b4 - Pubmed
- 7. Talenti G, Manara R, Brotto D, D'Arco F. High-resolution 3 T magnetic resonance findings in cochlear hypoplasias and incomplete partition anomalies: a pictorial essay. (2018) The British journal of radiology. 91 (1089): 20180120. doi:10.1259/bjr.20180120 - Pubmed
- 8. DEAFNESS, X-LINKED 2; DFNX2. OMIM #304400.