2021年 · 第04卷第04期

Preimplantation genetic diagnosis (PGD) uses molecular biological techniques to genetically diagnose embryos before in vitro fertilization. The information obtained through PGD can help clinicians select healthy embryos for implantation, prevent the transmission of inherited diseases and help affected families have healthy children. This paper reviews the development of PGD technology, the history of its application to hereditary hearing loss, and the general process of how PGD is applied to screen for hereditary hearing loss. The aim of this review is to demonstrate the reliability of PGD in the primary prevention of hereditary hearing loss, assist clinicians in counseling patients at risk of transmitting an inherited disease, and explore the journey from PGD to in vitro fertilization. Given that the application of PGD technology to hereditary hearing loss varies in different countries and regions, there is still a long way to go before PGD is routinely applied for the primary prevention of hereditary hearing loss.

Sensorineural hearing loss is the most common sensory deficit in humans, with an estimated prevalence of 1 in 500 newborns. Approximately half of childhood hearing loss is attributed to genetic factors and can be classified as syndromic or non-syndromic based on the inheritance pattern. The ion channel genes KCNQ1, KCNE1, KCNQ4, P2RX2, TMC1, KCNJ10, and CACNA1D have frequently been associated with genetic hearing loss. Because of the important roles these genes play in cochlear hair cell function and the auditory pathways, mutations in these genes that result in impaired ion channel function can lead to hereditary hearing loss. The main purpose of this review was to examine the latest research progress on the functional roles, inheritance pattern, gene expression, protein structure, clinical phenotypes, mouse models, and possible treatments of the most commonly studied ion channels associated with inherited deafness. A comprehensive summary could help highlight ion channels that should be investigated as potential drug targets for the treatment of inherited deafness.

KCNQ4 gene mutation can lead to deafness non-syndromic autosomal dominant 2A, which is a type of autosomal dominant non-syndromic hearing loss. Deafness non-syndromic autosomal dominant 2A patients with KCNQ4 gene mutation usually present with symmetrical, delayed, progressive high-frequency-affected hearing loss, which eventually can involve all frequencies. In this article, we comprehensively reviewed the research on the role and function of KCNQ4 gene in genetic hearing loss. We discussed the pathological and physiological mechanisms of KCNQ4 gene and the related clinical phenotypes of KCNQ4 gene mutations. We also reviewed the latest developments in the treatment of KCNQ4 gene mutation-related genetic hearing loss, including selective potassium channel activation drugs and gene therapy.

The vestibular system involves high-level sensory and cognitive processes, such as spatial perception, balance control, visual stability, and emotional control. Vestibular dysfunction can induce vertigo, blurred vision, postural imbalance, walking instability, and spatial discomfort, which causes serious damage to health. It has long been known that after peripheral vestibular lesion, vestibular dysfunction may spontaneously recover. This is known as vestibular compensation. However, at least 20% to 30% of patients with vestibular disorders cannot yield vestibular compensation and remain with vestibular dysfunction for the rest of their lives. The exploration of the biological characteristics and regulatory factors of the loss and reestablishment of vestibular function will establish a new understanding of the mechanism of vestibular compensation and provide new tools and strategies for promoting vestibular rehabilitation. We aim to comprehensively review the mechanism of vestibular compensation and discuss future directions in this field.