X-Linked Gusher Disease DFNX2 in Children, a Rare Inner Ear Dysplasia with Mixed Hearing and Vestibular Loss

Abstract

Conductive hearing losses are typically present in disorders of the external/middle ear. However, there is a rare group of inner ear conditions called third windows that can also generate a conductive hearing loss. This is due to an abnormal connection between the middle and the inner ear or between the inner ear and the cranial cavity. X-linked gusher disorder is an extremely rare congenital inner ear dysplastic syndrome with an abnormal connection due to a characteristic incomplete cochlear partition type III and an incomplete internal auditory meatus fundus. The disorder is inherited in an X-linked fashion due to the mutation of the POU3F4 gene. We present two siblings diagnosed with the condition and their long-term follow-ups. They both presented audiovestibular symptoms and showed progressive mixed losses and bilateral vestibular weakness. They were treated with cochlear implant, digital amplification and with vestibular rehabilitation. Significant others around them were involved in their journey with the medical team, and in both, a very favourable outcome was achieved. This is the first time that we have reported evolving audiovestibular function with vestibular quantification in X-linked gusher disorder and emphasize on the multidisciplinary holistic approach to manage these children effectively.

Suppression head impulse test in children—experiences in a tertiary paediatric vestibular centre

“…Evidence about the HIMP paradigm in children is limited but emerging ( 9 ). The procedure can be safely and effectively executed in children, but the outcome norms may be different ( 21 ) and indeed every individual laboratory should have their own norms ( 14 ). Vestibular physiology may be different in adults as compared to children; as in the latter, the system is under a process of development and maturation ( 9 ).…”

“…We did not consider saccade clustering and PR score as these parameters are still being researched and experimental without much consensus especially in children. We had already established our HIMP norms where VOR gains range from 0.9 to 1 in horizontal canals and 0.6 to 0.8 in vertical canals between the ages 6 and 18 years ( 14 ). All the HIMP and SHIMP outputs were analyzed by two senior pediatric audiovestibular physicians, and agreement was reached in terms of validity, exclusion of artifacts, and presence of meaningful saccades.…”

“…Finally, the children underwent a cervical-evoked vestibular myogenic potential test (cVEMP) with Neurosoft 2019. Our VEMP laboratory norms include asymmetry up to 26% and thresholds of 80 ≥ dBnHL between the ages of 4 and 16 years ( 14 ).…”

“…This is essential for a holistic management approach to manage disorders of balance function in children where cognitive and situational counseling are pivotal for both children affected and their carers/parents to maximize favorable outcome. Managing children with such disorders is quite different from what is practiced in adults due to the important premise that the vestibular system takes a significant part in overall development of children in several domains including motor skills, playground activities, navigation, and cognition ( 14 ).…”

Posterior Semicircular Canal Dehiscence with Vestibulo-Ocular Reflex Reduction for the Affected Canal at the Video-Head Impulse Test: Considerations to Pathomechanisms

“…Even though aural fullness and autophony can also be found in both patulous Eustachian tube and SCD, patients with a patulous Eustachian tube generally have autophony for their own breath sounds, while patients with SCD usually do not [9]. Besides SCD, other conditions resulting in a TMWM have been described over the years, including an enlarged vestibular aqueduct, X-linked gusher disorder and cochlear dehiscence either involving the internal carotid artery or the facial nerve (FN) [3,5,6,[10][11][12][13][14]. Despite being rare, posterior SCD (PSCD) represents the second most common SCD after SSCD, with a 2% incidence among adult patients and a variable incidence ranging from 1.3 to 43% in the pediatric population [15][16][17][18].…”