BACKGROUND: Leber hereditary optic neuropathy (LHON) typically presents in young adults as bilateral painless subacute visual loss. Prevalence data are scarce. The aim of this study was to examine the validity of different ascertainment sources used in population-based rare diseases registries to detect cases, and to explore the impact of a capture-recapture method in the estimation of the prevalence of LHON in the Autonomous Community of Madrid (ACM) in 2022.
METHODS: Descriptive cross-sectional population-based study. Potential LHON cases were detected by automatic capture from the healthcare information sources usually explored for the Regional Registry for Rare Diseases (SIERMA). Ophthalmologists provided data from their clinical registry. Positive predictive values (PPV) and sensitivity with 95% confidence intervals (CI) were estimated. Global and by sex prevalences were calculated with confimed cases and with those estimated by the capture-recapture method.
RESULTS: A total of 102 potential LHON cases were captured from healthcare information sources, 25 of them (24.5%) finally were confirmed after revision, with an overall PPV of 24.5% (95%CI 17.2-33.7). By source, the electronic clinical records of primary care had the highest PPV (51.2, 95%CI 36.7-65.4). The ophthalmologists clinical registry provided 22 cases, 12 of them not detected in the automatic capture sources. The clinical registry reached a sensitivity of 59.5% (95%CI 43.5-73.6) and the combination of automatic capture sources reached a 67.6% (95%CI: 51.5-80.4). The total confirmed cases were 37, with a mean age of 48.9 years, and a men: women ratio of 2.4:1. Genetic information was recovered in 27 cases, with the m.3460 mutation being the most frequent (12 cases). The global prevalence was 0.55 cases/100,000 inhabitants (95%CI 0.40-0.75), and with the capture-recapture method reached 0.79 cases/100,000 (95%CI 0.60-1.03), a 43.6% higher, 1.15 cases/100,000 (95%CI 0.83-1.58) in men and 0.43 cases/100,000 (95%CI 0.26-0.70) in women.
CONCLUSIONS: The prevalence of LHON estimated in the ACM was lower than in other European countries. Population-based registries of rare diseases require the incorporation of confirmed cases provided by clinicians to asure the best completeness of data. The use of more specific coding for rare diseases in healthcare information systems would facilitate the detection of cases. Further epidemiologic studies are needed to assess potential factors that may influence the penetrance of LHON.

BACKGROUND: The pathophysiology of toxico-nutritional optic neuropathies remains debated, with no clear understanding of the respective roles played by the direct alcohol toxicity, smoking and the often associated vitamin deficiencies, which are risk factors for optic neuropathy. Our aim was to investigate genetic susceptibility in patients with bilateral infraclinical optic neuropathy associated with chronic alcohol use disorder.
METHODS: This retrospective cohort study included 102 visually asymptomatic patients with documented alcohol use disorder from a French reference center. Optic neuropathy was identified with optical coherence tomography (OCT), after which genetic susceptibility in the group of affected patients was investigated. Genetic testing was performed using panel sequencing of 87 nuclear genes and complete mitochondrial DNA sequencing.
RESULTS: Optic neuropathy was detected in 36% (37/102) of the included patients. Genetic testing of affected patients disclosed two patients (2/30, 6.7%) with optic neuropathy associated with pathogenic variants affecting the SPG7 gene and five patients (5/30, 16.7%) who harbored variants of uncertain significance close to probable pathogenicity in the genes WFS1, LOXL1, MMP19, NR2F1 and PMPCA. No pathogenic mitochondrial DNA variants were found in this group.
CONCLUSIONS: OCT can detect presence of asymptomatic optic neuropathy in patients with chronic alcohol use disorder. Furthermore, genetic susceptibility to optic neuropathy in this setting is found in almost a quarter of affected patients. Further studies may clarify the role of preventative measures in patients who might be predisposed to avoidable visual loss and blindness.

Dominant optic atrophy (DOA) is one of the most prevalent forms of hereditary optic neuropathies and is mainly caused by heterozygous variants in OPA1, encoding a mitochondrial dynamin-related large GTPase. The clinical spectrum of DOA has been extended to a wide variety of syndromic presentations, called DOAplus, including deafness as the main secondary symptom associated to vision impairment. To date, the pathophysiological mechanisms underlying the deafness in DOA remain unknown. To gain insights into the process leading to hearing impairment, we have analyzed the Opa1delTTAG mouse model that recapitulates the DOAplus syndrome through complementary approaches combining morpho-physiology, biochemistry, and cellular and molecular biology. We found that Opa1delTTAG mutation leads an adult-onset progressive auditory neuropathy in mice, as attested by the auditory brainstem response threshold shift over time. However, the mutant mice harbored larger otoacoustic emissions in comparison to wild-type littermates, whereas the endocochlear potential, which is a proxy for the functional state of the stria vascularis, was comparable between both genotypes. Ultrastructural examination of the mutant mice revealed a selective loss of sensory inner hair cells, together with a progressive degeneration of the axons and myelin sheaths of the afferent terminals of the spiral ganglion neurons, supporting an auditory neuropathy spectrum disorder (ANSD). Molecular assessment of cochlea demonstrated a reduction of Opa1 mRNA level by greater than 40%, supporting haploinsufficiency as the disease mechanism. In addition, we evidenced an early increase in Sirtuin 3 level and in Beclin1 activity, and subsequently an age-related mtDNA depletion, increased oxidative stress, mitophagy as well as an impaired autophagic flux. Together, these results support a novel role for OPA1 in the maintenance of inner hair cells and auditory neural structures, addressing new challenges for the exploration and treatment of OPA1-linked ANSD in patients.

A 29-year-old female with no family history presented with bilateral progressive blurred vision. Her symptoms appeared at 12-years-old and her visual acuity had since deteriorated from 0.6 to 0.2 bilaterally with decreased critical flicker frequency and bilateral central scotomas. She did not have a relative afferent pupillary defect. Fundoscopy revealed no distinct disc hyperaemia, atrophy, or peripapillary telangiectatic vessels. The retinal nerve fibre layer appeared normal on optical coherence tomography in each eye; however, loss of the interdigitation zone and the disruption of the ellipsoid zone at the fovea were observed in both eyes. Multifocal electroretinography revealed decreased amplitudes at both macula regions. Mitochondrial deoxyribonucleic acid analysis identified an m.14502T>C mutation, one of the primary mutations causing Leber\'s hereditary optic neuropathy (LHON). Despite the presence of a marked LHON mutation, however, she was clinically diagnosed as having an occult macular dystrophy. There have only been five previous case reports, all of which were sporadic, which detail the clinical characteristics of the m.14502T>C mutation. The m.14502T>C phenotype is somewhat consistent with that of the other major mutations, including young onset, bilateral progressive visual impairment, and a typical LHON fundus. Nevertheless, m.14502T>C alone has an extremely low penetrance and its phenotype may be minimal or subclinical, as seen in our case. Since little is known about the clinical course of the m.14502T>C mutation it may be possible that the LHON phenotype may appear in later stages of life. Moreover, m.14502T>C may function as a modifier gene, which alters the phenotype of other coexisting major LHON mutations, including penetrance and the severity of the disease, through synergistic effects.

The options for genetic testing continue to grow for ocular conditions, including optic atrophy, anterior segment dysgenesis, cataracts, corneal dystrophy, nystagmus, and glaucoma. Gene panels can vary in content and coverage, as we and others have evaluated in inherited retinal disease (IRD).
To describe gene panel testing options for inherited eye disease phenotypes and their differences. This review is important for making diagnostic decisions.
A licensed, certified genetic counselor (RP) used Concert Genetics and the search terms optic atrophy, corneal dystrophy, cataract, glaucoma, anterior segment dysgenesis, microphthalmia/anophthalmia, and nystagmus to identify available testing options performed by CLIA-certified commercial genetic testing laboratories. Other co-authors were surveyed with respect to genetic panels used for the indications of interest. Ophthalmic panels were then compared using Concert Genetics in addition to their own websites.
Panels from each clinical category were included and summarized. This comparison highlighted the differences and similarities between panels so that clinicians can make informed decisions.
Access to genetic testing is increasing. The diagnostic yield of genetic testing is increasing. Each panel is different, so phenotyping or characterizing clinical characteristics that may help predict a specific genotype, as well as pre-test hypotheses regarding a genotype, should shape the choice of panels.

OBJECTIVE: To describe a case of hereditary spastic ataxia (HSP) presenting with childhood optic nerve atrophy and report a novel homozygous variant in the SPG7 gene.
METHODS: A 57-year-old man suffering from progressive optic nerve atrophy since childhood eventually underwent genetic testing. A targeted whole exome gene sequencing panel for optic neuropathy identified a novel homozygous variant in the SPG7 gene, c.2T > G, p.(Met?), which likely abolished production of paraplegin, an inner mitochondrial membrane protein. Subsequent neurologic examination revealed subtle signs of spastic paraplegia and ataxia in keeping with the genetic diagnosis of SPG7.
CONCLUSIONS: Spastic paraplegia 7 (SPG7) is an autosomal recessive form of the neurodegenerative disorder HSP. Pure HSP is characterized by spastic paraparesis in the lower limbs, whereas complicated HSP presents additional neurological manifestations. This case report adds to the evidence that SPG7 can present with childhood optic nerve atrophy, preceding the characteristic SPG7 manifestations. SPG7 should be considered in the workup of suspected hereditary optic neuropathy.

Hereditary optic neuropathy (HON) is a group of genetically heterogeneous diseases that cause optic nerve atrophy and lead to substantial visual impairment. HON may present with optic nerve atrophy only or in association with various systemic abnormalities. Although a genetic survey is indispensable for diagnosing HON, conventional sequencing techniques could render its diagnosis challenging. In this study, we attempted to explore the genetic background of patients with HON in Taiwan through capture-based next-generation sequencing targeting 52 HON-related genes. In total, 57 patients from 48 families were recruited, with 6 patients diagnosed as having Leber hereditary optic neuropathy through initial screening for three common variants (m.3460G>A, m.11778G>A, m.14484T>C). Disease-causing genotypes were identified in 14 (33.3%) probands, and OPA1 variants were the most prevalent cause of autosomal HON. Exposure to medications such as ethambutol could trigger an attack of autosomal dominant optic atrophy. WFS1 variants were identified in three probands with variable clinical features in our cohort. Hearing impairment could occur in patients with OPA1 or WFS1 variants. This is the first comprehensive study investigating the genetic characteristics of HON in Taiwan, especially for autosomal HON. Our results could provide useful information for clinical diagnosis and genetic counseling in this field.

OBJECTIVE: Patients with autosomal optic neuropathies (AON) may develop microcystic macular degeneration (MMD), observed on retinal optical coherence tomography (OCT) examination. This study aimed to report the prevalence of MMD in AON patients and to assess the consequences of MMD on retinal architecture.
METHODS: Retrospective single-center study conducted between 2001 and 2018. Patients affected by AON secondary to OPA1 or WFS1 gene mutations were included. The following data were collected: visual acuity, macular volume, vitreomacular interface and presence or absence of MMD.
RESULTS: Forty-two subjects (34 OPA1, 8 WFS1) were included. MMD was found in 12 (29%) patients, i.e. 6 of the 8 WFS1 patients (75%) and 6 of the 34 OPA1 patients (17%). In cases with MMD, total retinal volume was greater (P=0.02) in accordance with thickening of the inner nuclear layer (P<0.001). WFS1 subjects had the highest total retinal volume (P=0.01), in relation to a thickening of the inner plexiform layer (P=0.02), inner nuclear layer (P<0.001) and outer plexiform layer (P=0.002). MMD was significantly associated with the WFS1 mutation (P<0.001). No significant association was found between the presence of vitreomacular adhesion and MMD.
CONCLUSIONS: MMD was found in 29% of patients affected by AON and was more frequent in cases with a WFS1 gene mutation. MMD appears to be related to primary ganglion cell degeneration and Müller cell dysfunction. The vitreomacular interface does not appear to play a role in the occurrence of MMD.

OBJECTIVE: Familial Dysautonomia (FD) disease, lacks a useful biomarker for clinical monitoring. In this longitudinal study we characterized the structural changes in the macula, peripapillary and the optic nerve head (ONH) regions in subjects with FD.
METHODS: Data was consecutively collected from subjects attending the FD clinic between 2012 and 2019. All subjects were imaged with spectral-domain Optical Coherence Tomography (OCT). Global and sectoral measurements of mean retinal nerve fiber layer (RNFL) and macular ganglion cell and inner plexiform layer (GCIPL) thickness, and ONH parameters of rim area, average cup-to-disc (C:D) ratio, and cup volume were used for the analysis. The best fit models (linear, quadratic and broken stick linear model) were used to describe the longitudinal change in each of the parameters.
RESULTS: 91 subjects (149 eyes) with FD of ages 5-56 years were included in the analysis. The rate of change for average RNFL and average GCIPL thicknesses were significant before reaching a plateau at the age of 26.2 for RNFL and 24.8 for GCIPL (- 0.861 µm/year (95% CI - 1.026, - 0.693) and - 0.553 µm/year (95% CI - 0.645, - 0.461), respectively). Significant linear rate of progression was noted for all ONH parameters, except for a subset of subjects (24%), with no cupping that did not show progression in any of the ONH parameters.
CONCLUSIONS: The rapidly declining RNFL and GCIPL can explain the progressive visual impairment previously reported in these subjects. Among all structural parameters, ONH parameters might be most suitable for longitudinal follow-up, in eyes with a measurable cup.

UNASSIGNED: To evaluate the ophthalmic, systemic, and genetic characteristics of patients with Wolfram syndrome.
UNASSIGNED: In total, 13 patients with suspected or clinically diagnosed Wolfram syndrome underwent ophthalmic and systemic examinations and genetic analyses for Wolfram syndrome between August and October 2018.
UNASSIGNED: The mean age of the subjects was 24.2 ± 7.1 years, of which 5 (38.5%) subjects were male and 8 (61.5%) were female. The mean best-corrected visual acuity ranged from counting fingers to 20/40, with a mean of 20/250 (1.10 ± 0.69 logarithm of the minimum angle of resolution). Dyschromatopsia was present in all patients (100%). There was a severe decrease in the average peripapillary retinal nerve fiber layer and macular ganglion cell-inner plexiform layer thicknesses (54.7 ± 6.5 and 51.9 ± 4.8 µm, respectively). Optical coherence tomography angiography showed significantly lower whole-image, inside disk, and peripapillary vessel densities in the patients with Wolfram syndrome than in the healthy controls (p < 0.001 for all). All patients who underwent genetic analyses had mutations in the WFS1 gene. Moreover, two novel mutations, p.Met623Trpfs*2 (c.1867delA) and p.Arg611Profs*9 (c.1832_11847del16) at exon 8, were detected. The frequency of systemic findings was as follows: optic atrophy (100%), diabetes mellitus (92.3%), central diabetes insipidus (38.5%), sensorineural hearing loss (38.5%), and presence of urological (30.8%), psychiatric (30.8%), and neurological (23.1%) diseases.
UNASSIGNED: Wolfram syndrome is a rare genetic disorder that can be associated with severe ophthalmic and systemic abnormalities. All patients who present with unexplained optic atrophy should be evaluated for Wolfram syndrome, even if they do not have diabetes mellitus because optic atrophy can sometimes manifest before diabetes mellitus.