Comprehensive analysis of two hotspot codons in the TUBB4B gene and associated phenotypes.

Our purpose was to elucidate the genotype and ophthalmological and audiological phenotype in TUBB4B-associated inherited retinal dystrophy (IRD) and sensorineural hearing loss (SNHL), and to model the effects of all possible amino acid substitutions at the hotspot codons Arg390 and Arg391. Six patients from five families with heterozygous missense variants in TUBB4B were included in this observational study. Ophthalmological testing included best-corrected visual acuity, fundus examination, optical coherence tomography, fundus autofluorescence imaging, and full-field electroretinography (ERG). Audiological examination included pure-tone and speech audiometry in adult patients and auditory brainstem response testing in a child. Genetic testing was performed by disease gene panel analysis based on genome sequencing. The molecular consequences of the substitutions of residues 390 and 391 on TUBB4B and its interaction with α-tubulin were predicted in silico on its three-dimensional structure obtained by homology modelling. Two independent patients had amino acid exchanges at position 391 (p.(Arg391His) or p.(Arg391Cys)) of the TUBB4B protein. Both had a distinct IRD phenotype with peripheral round yellowish lesions with pigmented spots and mild or moderate SNHL, respectively. Yet the phenotype was milder with a sectorial pattern of bone spicules in one patient, likely due to a genetically confirmed mosaicism for p.(Arg391His). Three patients were heterozygous for an amino acid exchange at position 390 (p.(Arg390Gln) or p.(Arg390Trp)) and presented with another distinct retinal phenotype with well demarcated pericentral retinitis pigmentosa. All showed SNHL ranging from mild to severe. One additional patient showed a variant distinct from codon 390 or 391 (p.(Tyr310His)), and presented with congenital profound hearing loss and reduced responses in ERG. Variants at codon positions 390 and 391 were predicted to decrease the structural stability of TUBB4B and its complex with α-tubulin, as well as the complex affinity. In conclusion, the twofold larger reduction in heterodimer affinity exhibited by Arg391 substitutions suggested an association with the more severe retinal phenotype, compared to the substitution at Arg390.

Type 1 and type 2 torpedo maculopathy.

PURPOSE: To analyze torpedo maculopathy (TM) and to report the characteristics of the disease. METHODS: Retrospective study. The review of a database for clinical diagnosis identified eight patients with TM lesions in the retina between 2016 and 2022. Multimodal imaging was used to analyze the cases. RESULTS: All cases were unilateral, asymptomatic, and hypopigmented. They were associated by surrounding hyperpigmented retinal pigment epithelium changes to varying degrees. All lesions were located in the temporal retina on the horizontal axis, pointing towards the fovea, except for one patient with a lesion inferior to the fovea. Optical coherence tomography imaging revealed a normal inner retina in all eyes. In the area of the TM lesion, attenuation of the interdigitation zone was seen in mild cases (three cases). All other five patients had thinning of the outer nuclear layer and loss of ellipsoid zone and interdigitation zone of the TM lesion. Four of these cases had a subretinal cavitation/cleft, and two of them additionally an inner choroidal excavation. No patient had any sign of choroidal neovascularization. The average age for patients with type 1 TM was 18 years and for type 2 TM 16.5 years. CONCLUSION: In this large case series, we could not detect an age difference between the different types of the TM. Contrary to previous discussions, type 2 TM can also occur in young patients.

Impact of A-Scan Rate on Image Quality and Acquisition Time in OCT.

PURPOSE: This study aims to examine the impact of the A-scan rate in optical coherence tomography (OCT) on scan quality and acquisition time. METHODS: Two horizontal OCT scans per scan rate (20, 85, 125 kHz) of the right eye were captured with the same OCT device (Spectralis SHIFT, HRA + OCT, Heidelberg Engineering GmbH, Heidelberg, Germany) of patients who presented to the inherited retinal dystrophies consultation, thus predominantly challenging patients due to reduced fixation ability. Scan quality was measured by the Q score, a signal-to-noise-ratio (SNR). Acquisition time was measured in seconds. RESULTS: Fifty-one patients were included in the study. The highest quality was seen for an A-scan rate of 20 kHz (44.49 dB), succeeded by scans of an A-Scan rate of 85 kHz (38.53 dB) and of 125 kHz (36.65 dB). Differences in scan quality between the various A-scan rates were statistically significant. The acquisition time seen for an A-scan rate of 20 kHz (6.45 s) was significantly longer than those seen for an A-Scan rate of 85 kHz (1.51 s) and of 125 kHz (1.69 s). CONCLUSION: An A-scan rate of 20 kHz resulted in a significantly higher scan quality but also a significantly longer acquisition time compared to scan rates of 85 kHz and 125 kHz. Differences between an A-scan rate of 85 kHz and 125 kHz were marginal.

Efficacy of Adjuvants in Ophthalmic Regional Anesthesia: A Systematic Review and Network Meta-analysis.

PURPOSE: This network meta-analysis aims to determine the differences between adjuvants that are used in combination with local anesthetics for ophthalmic regional anesthesia. DESIGN: Systematic review and network meta-analysis. METHODS: A systematic literature search for randomized controlled trials, comparing the impact of adjuvants in ophthalmic regional anesthesia, in Embase, CENTRAL, MEDLINE and Web of Science was performed. Risk of bias was evaluated using the Cochrane risk of bias tool. Frequentist network meta-analysis was performed using a random effects model with saline as the comparator. Primary endpoints were the onset and the duration of sensory block and globe akinesia, as well as the duration of analgesia. Summary measure was the ratio of means (ROM). Secondary endpoints were the rates of side effects and adverse events. RESULTS: A total of 39 trials were identified as eligible for network meta-analysis, including 3046 patients. In all, 17 adjuvants were compared in the most extensive network (onset of globe akinesia). The addition of fentanyl (F), clonidine (C), or dexmedetomidine (D) showed the best overall results. Onset of sensory block was as follows: F 0.58 (CI = 0.47-0.72), C 0.75 (0.63-0.88), D 0.71 (0.61-0.84); onset of globe akinesia: F 0.71 (0.61-0.82), C 0.70 (0.61-0.82), D 0.81 (0.71-0.92); duration of sensory block: F 1.20 (1.14-1.26), C 1.22 (1.18-1.27), D 1.44 (1.34-1.55); duration of globe akinesia: F 1.38 (1.22-1.57), C 1.45 (1.26-1.67), D 1.41 (1.24-1.59); and duration of analgesia: F 1.46 (1.33-1.60), C 1.78 (1.63-1.96), D 1.41 (1.28-1.56). CONCLUSIONS: The addition of fentanyl, clonidine, or dexmedetomidine showed beneficial effects regarding onset and duration of sensory block and globe akinesia.

Biallelic Variants in TULP1 Are Associated with Heterogeneous Phenotypes of Retinal Dystrophy.

Biallelic pathogenic variants in TULP1 are mostly associated with severe rod-driven inherited retinal degeneration. In this study, we analyzed clinical heterogeneity in 17 patients and characterized the underlying biallelic variants in TULP1. All patients underwent thorough ophthalmological examinations. Minigene assays and structural analyses were performed to assess the consequences of splice variants and missense variants. Three patients were diagnosed with Leber congenital amaurosis, nine with early onset retinitis pigmentosa, two with retinitis pigmentosa with an onset in adulthood, one with cone dystrophy, and two with cone-rod dystrophy. Seventeen different alleles were identified, namely eight missense variants, six nonsense variants, one in-frame deletion variant, and two splice site variants. For the latter two, minigene assays revealed aberrant transcripts containing frameshifts and premature termination codons. Structural analysis and molecular modeling suggested different degrees of structural destabilization for the missense variants. In conclusion, we report the largest cohort of patients with TULP1-associated IRD published to date. Most of the patients exhibited rod-driven disease, yet a fraction of the patients exhibited cone-driven disease. Our data support the hypothesis that TULP1 variants do not fold properly and thus trigger unfolded protein response, resulting in photoreceptor death.

Opticopathy Caused by Endoprosthesis-Related Cobalt Intoxication. / Optikopathie durch Hüft-TEP-bedingte Kobaltintoxikation.

Cobalt intoxication is a rare cause of toxic opticopathy, and may be caused by metal endoprostheses. Since its clinical appearance is unspecific and the incidence low, diagnosis is challenging. Due to the dramatic consequences of delayed treatment, cobalt intoxication should be considered as a rare differential diagnosis of bilateral loss of vision in patients with appropriate history.