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Objective: To describe the characteristics of the clinical presentation, diagnosis, surgical methods, and outcomes of patients with otogenic cerebrospinal fluid (CSF) leakage secondary to congenital inner ear dysplasia. Methods: A retrospective review was performed of 18 patients with otogenic CSF leakage secondary to inner ear dysplasia who underwent surgery in our group from 2007 to 2017 and had a follow-up of at least 4 months. The average length of follow-up was three years. The characteristics of the clinical presentations of all patients, such as self-reported symptoms, radiographic findings, surgical approaches and methods of repair, position of the leakage during surgery, and postoperative course, including the success rate of surgery, are presented. Results: The patients presented mostly with typical symptoms of meningitis, severe hearing impairment, and CSF otorrhea or rhinorrhea. All 18 patients had at least one previous episode of meningitis accompanied by a severe hearing impairment. The preoperative audiograms of 17 patients showed profound sensorineural hearing loss, and one patient had conductive hearing loss. Twelve patients presented with an initial onset of otorrhea, and two had accompanying rhinorrhea. Six patients complained of rhinorrhea, two of whom were misdiagnosed with CSF rhinorrhea and underwent transnasal endoscopy at another hospital. High-resolution computed tomography (HRCT) images can reveal developments in the inner ear, such as expansion of a vestibular cyst, unclear structure of the semicircular canal or cochlea, or signs of effusion in the middle ear or mastoid, which strongly suggest the possibility of CSF otorrhea. The children in the study suffered more severe dysplasia than adults. All 18 patients had CSF leakage identified during surgery. The most common defect sites were in the stapes footplates (55.6%), and 38.9% of patients had a leak around the oval window. One patient had a return of CSF otorrhea during the postoperative period, which did not re-occur following a second repair. Conclusions: CSF otorrhea due to congenital inner ear dysplasia is more severe in children than in adults. The most common symptoms were meningitis, hearing impairment, and CSF otorrhea or rhinorrhea. HRCT has high diagnostic accuracy for this disease. The most common fistula site was around the oval window, including the stapes footplates and the annular ligament.

BackgroundThe 1555A > G mutation is the most common cause of aminoglycoside-induced and non-syndromic deafness. However, the variable clinical phenotype and incomplete penetrance of A1555G-induced hearing loss complicate our understanding of this mutation. Environmental factors, nuclear genes, mitochondrial haplotypes/variants and a possible threshold effect have been reported to may be involved in its manifestation.MethodsHere, we performed a clinical, molecular, genetic and phylogenic analysis in a six-generation Chinese family.ResultsA clinical evaluation revealed that affected individuals without aminoglycoside exposure developed hearing loss extending gradually from 12000 Hz to 8000 Hz and then to 4000 Hz. Using pyrosequencing, we detected an identical homoplasmic 1555A > G mutation in all individuals except one. We did not find any correlation between the mutation load and the severity of hearing loss. T123N coexisted with the 1555A > G mutation in six affected subjects in our pedigree. Analysis of the complete mtDNA genome of this family revealed that this family belonged to haplotype B4C1C and exhibited high penetrance. Upon the inclusion of subjects that had been exposed to aminoglycosides, the penetrance of the hearing loss was 63.6%.; without exposure to aminoglycosides, it was 51.5%. This pedigree and another reported Chinese pedigree share the same haplotype (B4C1C) and lack functionally significant mitochondrial tRNA variants, but nevertheless they exhibit a different penetrance of hearing loss.ConclusionsOur results imply that the factors responsible for the higher penetrance and variable expression of the deafness associated with the 1555A > G mutation in this pedigree may not be mtDNA haplotype/variants, but rather nuclear genes and/or aminoglycosides.