OBJECTIVES: The purinergic receptor P2X2 (P2RX2) encodes an ATP-gated ion channel permeable to Na⁺, K⁺, and especially Ca²⁺. Loss-of-function mutations in P2RX2 are known to cause autosomal dominant nonsyndromic deafness 41 (DFNA41), which manifests as high-frequency hearing loss, accelerated presbycusis, and increased susceptibility to noise-induced damage. Zebrafish, owing to their small size, rapid development, high fecundity, transparent embryos, and high gene conservation with humans, provide an ideal model for studying human diseases and developmental mechanisms. This study aims to generate a p2rx2 knockout zebrafish model using CRISPR/Cas9 gene editing system to investigate the effect of p2rx2 deficiency on the auditory system, providing a basis for understanding P2RX2-related hearing loss and developing gene therapy strategies. METHODS: Two CRISPR targets (sgRNA1 and sgRNA2) spaced 47 bp apart were designed within the zebrafish p2rx2 gene. Synthesized sgRNAs and Cas9 protein were microinjected into single-cell stage Tübingen (TU)-strain zebrafish embryos. PCR and gel electrophoresis verified editing efficiency at 36 hours post-fertilization (hpf). Surviving embryos were raised to adulthood (F0), tail-clipped, genotyped, and screened for positive mosaics. F1 heterozygotes were generated by outcrossing, and F2 homozygous mutants were obtained by intercrossing. Polymerase chain reaction (PCR) combined with sequencing verified mutation type and heritability. At 5 days post-fertilization (dpf), YO-PRO-1 staining was used to examine hair cell morphology and count in lateral line neuromasts and the otolith region. Auditory evoked potential (AEP) thresholds at 600, 800, 1 000, and 2 000 Hz were measured in nine 4-month-old wild type and mutant zebrafish per group. RESULTS: A stable p2rx2 knockout zebrafish line was successfully established. Sequencing revealed a 66 bp insertion at the first target site introducing a premature stop codon (TAA), leading to early termination of protein translation and loss of function. Embryos developed normally with no gross malformations. At 5 dpf, mutants exhibited significantly reduced hair cell density in the otolith region compared with wild type, although lateral line neuromasts were unaffected. AEP testing showed significantly elevated auditory thresholds at all 4 frequencies in homozygous mutants compared with wild type (all P<0.001), indicating reduced hearing sensitivity. CONCLUSIONS We successfully generated a p2rx2 loss-of-function zebrafish model using CRISPR/Cas9 technology. p2rx2 deficiency caused hair cell defects in the otolith region and increased auditory thresholds across frequencies, indicating its key role in maintaining zebrafish auditory hair cell function and hearing perception. The phenotype's restriction to the otolith region suggests tissue-specific roles of p2rx2 in sensory organs. This model provides a valuable tool for elucidating the molecular mechanisms of P2RX2-related hearing loss and for screening otoprotective drugs and developing gene therapies.
Animals ; Zebrafish/genetics* ; Receptors, Purinergic P2X2/deficiency* ; CRISPR-Cas Systems/genetics* ; Gene Knockout Techniques ; Phenotype ; Zebrafish Proteins/genetics* ; Disease Models, Animal

OBJECTIVES: Diabetes mellitus is closely associated with sudden sensorineural hearing loss (SSNHL), but no definitive evidence has established a causal relationship between type 1 diabetes mellitus (T1DM) and SSNHL. This study aims to investigate the impact of T1DM on SSNHL from a genetic perspective, providing insights for risk prediction and treatment strategies. METHODS: Genetic data related to exposure (T1DM) and outcome (SSNHL) were obtained from publicly available genome-wide association studies (GWAS). Instrumental variables were selected, and Mendelian randomization (MR) analysis was conducted to explore the causal association between T1DM and SSNHL. Inverse variance weighted (IVW) analysis was used as the primary method, with random-effects IVW serving as the main analytical approach. MR-Egger, weighted median, simple mode, and weighted mode analyses were utilized as supplementary methods. Cochran's Q test was applied to evaluate the heterogeneity of the selected instrumental variables, MR-PRESSO was applied to detect outliers, MR-Egger regression was used to assess horizontal pleiotropy and leave-one-out analysis was conducted to examine the robustness of individual single nucleotide polymorphisms (SNPs) on the overall results. RESULTS: A total of 127 SNPs were selected as instrumental variables for the MR analysis. IVW analysis demonstrated a genetically determined association between T1DM and SSNHL (OR=1.036, 95% CI 1.002 to 1.071, P=0.038). Forest plots and scatter plots indicated a causal relationship, suggesting that T1DM increases the risk of SSNHL. Cochran's Q test demonstrated no significant heterogeneity among SNPs (MR-Egger: Q=126.030, P=0.356; IVW: Q=126.450, P=0.373). The funnel plot appeared symmetrical, indicating that the selected instrumental variables were primarily related to exposure rather than potential confounding factors. The MR-Egger intercept was not significantly different from zero (P=0.527), indicating no evidence of horizontal pleiotropy among the SNPs. MR-PRESSO analysis did not identify any outlier SNPs (P=0.356). Leave-one-out analysis confirmed the robustness of the findings, as the results remained stable after removing individual SNPs. CONCLUSIONS Two-sample MR analysis supports the conclusion that T1DM patients have an increased risk of developing SSNHL.
Humans ; Mendelian Randomization Analysis ; Hearing Loss, Sensorineural/etiology* ; Diabetes Mellitus, Type 1/genetics* ; Genome-Wide Association Study ; Hearing Loss, Sudden/etiology* ; Polymorphism, Single Nucleotide ; Risk Factors ; Genetic Predisposition to Disease

OBJECTIVE: To screen and identify the frequency and characteristic of mutation in stereocilium-related gene Taperin of Chinese prelingual nonsyndromic hearing impairment with DNA microarray combined with PCR. METHOD: One hundred and thirty-four patients of prelingual nonsyndromic deafness and one hundred health individuals in China were investigated in this study. Genomic DNA was extracted from the patients and was subjected to DNA microarray to screen mutations in 4 most common genes. The samples that carried none of the common mutant alleles were subjected to PCR and sequenced to detect mutations in Taperin gene. RESULT: Ninteen out of one hundred and thirty-four patients of prelingual nonsyndromic deafness were detected carring common deafness gene with DNA microarray. Taperin gene were detected in one hundred and fifteen patients with PCR. A187S was detected in Taperin as hetrozygous state in 2 patients and their unaffected members of their family. It occurred at the evolutionary conservation of the amino acids of taperin according to alignment analysis. Two polymorphism, 157C>T and 318C>T, were found in the patients and the control group. CONCLUSION A novel Taperin mutation, A187S was detected in Chinese patients with prelingual nonsyndromic hearing loss, which may be relevant to hearing loss. Two polymorphism, 157C>T and 318C>T, were found in Chinese in our research. The carrier frequency for Taperin mutation is about 1.74% of prelingual nonsyndromic deafness in Chinese patients.
Adolescent ; Adult ; Asian Continental Ancestry Group ; genetics ; Child ; Child, Preschool ; China ; Deafness ; genetics ; Female ; Humans ; Male ; Mutation ; Proteins ; genetics ; Young Adult

OBJECTIVE: To review the clinical manifestations and management of nasal sinus mucoceles with visual loss. METHOD: Medical records for 23 patients of paranasal sinus mucoceles with visual impairment were re viewed retrospectively during 8-year period (from 2002 to 2010). Ten mucoceles were found in the frontal or fronto-ethmoidal sinuses, 6 in the ethmoidal sinuses, 7 in the sphenoidal or spheno-ethmoidal sinuses. Because the majority of early chief complaints were problems related to vision, patients were often seen by ophthalmologists first. Poor vision was more common in patients with sphenoid or spheno-ethmoidal sinus mucoceles because of their proximity to the optic nerve. CT and MRI were important tools for diagnosing nasal sinus mucocele. The patients received endoscopic surgery to remove mucocele and to decompress the optic nerve. Steroid therapy was given postoperatively and routine examination with endoscopy were carried out during follow-up. RESULT: Postoperatively, the majority of symptoms, such as exophthalmos, epiphora, diplopia and headache, disappeared in all patients. However, vision recovery was observed only in some patients. Recovery of vision depended on the timing of surgery and severity of initial visual loss. Delay in treatment can seriously compromise recovery of vision impairment. Moreover, patients without light perception before surgery had poor visual recovery even if optic nerve decompressions were performed. CONCLUSION Endoscopic surgery is effective to nasal sinus mucocele with visual loss. Because visual recovery depends on prompt diagnosis and surgical intervention, a good understanding of the disease and prompt imaging studies are important.
Adolescent ; Adult ; Cysts ; complications ; diagnosis ; surgery ; Female ; Humans ; Male ; Middle Aged ; Paranasal Sinus Diseases ; complications ; diagnosis ; surgery ; Retrospective Studies ; Vision, Low ; etiology ; Young Adult