Variants of the LOXHD1 gene, which are expressed in hair cells of the cochlea and vestibule, have been reported to cause a progressive form of autosomal recessive non-syndromic hereditary hearing loss, DFNB77. In this study, genetic screening was conducted on 8074 Japanese hearing loss patients utilizing massively parallel DNA sequencing to identify individuals with LOXHD1 variants and to assess their phenotypes. A total of 28 affected individuals and 21 LOXHD1 variants were identified, among which 13 were novel variants. A recurrent variant c.4212 + 1G > A, only reported in Japanese patients, was detected in 18 individuals. Haplotype analysis implied that this variation occurred in a mutational hot spot, and that multiple ancestors of Japanese population had this variation. Patients with LOXHD1 variations mostly showed early onset hearing loss and presented different progression rates. We speculated that the varying severities and progression rates of hearing loss are the result of environmental and/or other genetic factors. No accompanying symptoms, including vestibular dysfunction, with hearing loss were detected in this study. Few studies have reported the clinical features of LOXHD1-gene associated hearing loss, and this study is by far the largest study focused on the evaluation of this gene.

Background/Objectives: The OTOG gene is responsible for autosomal recessive non-syndromic sensorineural hearing loss and is assigned as DFNB18B. To date, 44 causative OTOG variants have been reported to cause non-syndromic hearing loss. However, the detailed clinical features for OTOG-associated hearing loss remain unclear. Methods: In this study, we analyzed 7065 patients with non-syndromic hearing loss (mean age 26.4 ± 22.9 years, 2988 male, 3855 female, and 222 without gender information) using massively parallel DNA sequencing for 158 target deafness genes. We identified the patients with biallelic OTOG variants and summarized the clinical characteristics. Results: Among the 7065 patients, we identified 14 possibly disease-causing OTOG variants in 26 probands, with 13 of the 14 variants regarded as novel. Patients with OTOG-associated hearing loss mostly showed congenital or childhood-onset hearing loss. They were considered to show non-progressive, mild-to-moderate hearing loss. There were no symptoms that accompanied the hearing loss in OTOG-associated hearing loss patients. Conclusions: We confirmed non-progressive, mild-to-moderate hearing loss as the clinical characteristics of OTOG-associated hearing loss. These findings will contribute to a better understanding of the clinical features of OTOG-associated HL and will be useful in clinical practice.

The PTPRQ gene has been identified as one of the genes responsible for non-syndromic sensorineural hearing loss (SNHL), and assigned as DFNA73 and DFNB84. To date, about 30 causative PTPRQ variants have been reported to cause SNHL. However, the detailed clinical features of PTPRQ-associated hearing loss (HL) remain unclear. In this study, 15,684 patients with SNHL were enrolled and genetic analysis was performed using massively parallel DNA sequencing (MPS) for 63 target deafness genes. We identified 17 possibly disease-causing PTPRQ variants in 13 Japanese patients, with 15 of the 17 variants regarded as novel. The majority of variants identified in this study were loss of function. Patients with PTPRQ-associated HL mostly showed congenital or childhood onset. Their hearing levels at high frequency deteriorated earlier than that at low frequency. The severity of HL progressed from moderate to severe or profound HL. Five patients with profound or severe HL received cochlear implantation, and the postoperative sound field threshold levels and discrimination scores were favorable. These findings will contribute to a greater understanding of the clinical features of PTPRQ-associated HL and may be relevant in clinical practice.

Branchio-oto-renal (BOR) syndrome is an autosomal dominant (AD) disorder characterized by branchiogenic malformation, hearing loss (HL), and renal anomalies [1,2]. The presence of branchiogenic mal...

Background/Objectives: MYH9 gene variants cause MYH9-related disease (MYH9-RD), which is also known as Epstein syndrome, Fechtner syndrome, May–Hegglin anomaly, and Sebastian syndrome. MYH9-RD is characterized by sensorineural hearing loss, macrothrombocytopenia, thrombocytopenia, hematuria/proteinuria, glomerulonephritis, cataracts purpura, and mucosal bleeding. In addition, the MYH9 gene is also known to be causative of autosomal dominant non-syndromic hearing loss (DFNA17). MYH9-RD is a relatively rare disorder, and the detailed clinical features and mutational spectra remain unclear. Methods: In this study, we performed next-generation sequencing analysis for 15,684 hearing loss patients and identified MYH9-associated hearing loss patients. Detailed clinical information was collected for these patients and summarized. Results: In this study, we identified 24 patients from 18 families with MYH9-associated hearing loss. We clarified the details of hearing deterioration observed in patients based on collected serial audiogram data. Some cases showed rapid hearing deterioration that worsened by about 50 dB within 5 years. Hearing loss is more likely to progress in patients with myosin head domain variants than in patients with myosin tail domain variants, but hearing loss in each set of patients finally deteriorates to bilateral profound hearing loss. Conclusions: In this study, we were able to clarify the detailed characteristics of MYH9-RD- and DFNA17-related hearing loss in a relatively large number of patients, particularly in some cases that showed rapid and asymmetrical hearing deterioration progressing to bilateral profound hearing loss. Our data will be useful for providing more appropriate treatment and follow-up for MYH9-associated hearing loss.