What is large vestibular aqueduct syndrome? Valvassori et al [13] first described the large vestibular aqueduct syndrome (LVAS) in 1978 and proposed the diagnostic criteria: the diameter of the midpoint between the external opening and the common pedicle of the vestibular aqueduct was measured, and the diameter of the vestibular aqueduct normally ranged from 0.4 to 1.0 mm, and when it was greater than 1.5 When the diameter of the vestibular canal is greater than 1.5 mm, the vestibular canal can be considered enlarged. Large vestibular aqueduct (LVA) is a congenital developmental anomaly of the temporal bone that can be associated with cochlear, semicircular canal, and vestibular malformations, such as cochlear hypoplasia, cochlear hypoplasia, undeveloped cochlea, or incomplete cochlear separation. The large vestibular canal is one of the common congenital inner ear malformations, resulting in deafness that is autosomal recessive non-syndromic hearing loss (NSHL) is closely related to mutations in the SLC26A4 gene [21-23], and deafness caused by SLC26A4 mutations is about 1-8% of congenital deafness [24]. The SLC26A4 gene is localized at 7q31, and the non-syndromic deafness DFNB4 and the PDS gene causing Pendred syndrome are in the same region [25], but DFNB4 deafness has temporal bone malformation and is not associated with thyroid abnormalities. the SLC26A4 gene contains 21 exons with an open reading frame of 2343 bp, and all exons except exon 20 are distributed with All exons except exon 20 have mutation sites. The mutations include missense mutations, nonsense mutations, splice sites, shift mutations and base deletions in large segments, most of which are missense mutations and can lead to protein truncation. The deafness-causing mechanism may be that the abnormal enlargement of the vestibular aqueduct disturbs the endolymphatic circulation balance, and the hyperosmolar fluid from the endolymphatic sac flows back into the cochlea causing damage to the auditory nerve epithelium, resulting in neurogenic deafness, while the enlarged vestibular aqueduct also suffers from endolymphatic sac reabsorption dysfunction, leading to disruption of electrolyte balance, and the accumulation of endolymphatic metabolites also disrupts cochlear hair cell function [26]. Features: fluctuating hearing loss (on and off, but with a general tendency to get worse); hearing manifests as sensorineural deafness or the presence of poor air-bone conduction at low frequencies; imaging (CT or MRI) suggests a large vestibular aqueduct; genetic testing may reveal PDS gene mutations! Treatment: Early mild deafness can be observed and care taken to avoid head trauma and other actions that can lead to an instantaneous increase in intracranial pressure! In case of sudden hearing loss within a short period of time, treatment of sudden deafness (including hormones, improvement of microcirculation, nerve nutrition, etc.) is indicated! Hearing aids may be considered in cases of severe deafness! If hearing aids are ineffective or unsatisfactory, cochlear implantation may be done.