Epidemiology and preventive measures in inherited retinal dystrophies in the Czech Republic.

Úvod: Dědičná onemocnění sítnice jsou jednou z nejčastějších příčin neléčitelné slepoty u dětí a mladších dospělých. V České republice nebyla tato onemocnění dosud předmětem systematického výzkumu. Cílem této práce bylo identifikovat, klinicky charakterizovat a molekulárně geneticky analyzovat pacienty s monogenně podmíněnými dědičnými chorobami sítnice a následně implementovat do klinické praxe preventivní a léčebná opatření. Materiál a metody: U pacientů s různými geneticky podmíněnými chorobami sítnice a jejich rodinných příslušníků jsme provedli komplexní klinické vyšetření, genealogický rozbor a molekulárně genetickou analýzu. Detailní oční vyšetření zahrnovalo optickou koherenční tomografii se spektrální doménou a fotodokumentaci včetně autofluorescence fundu. DNA byla izolována ze vzorků venózní krve, popř. buněk bukální sliznice. Příčinné varianty byly hledány pomocí Sangerova a masivně paralelního sekvenování a jejich patogenita prokazována v kontextu dříve publikovaných poznatků, pomocí bioinformatické analýzy a sledováním segregace u rodinných příslušníků. Výsledky: Ve formě publikačních výstupů bylo charakterizováno 103 jedinců ze 76 českých rodin se známkami monogenně dědičných dystrofií sítnice. Konkrétně jsme popsali klinické a molekulárně genetické nálezy u pacientů s retinitis...Introduction: Inherited retinal diseases (IRDs) are one of the most common causes of incurable blindness in children and young adults. In the Czech Republic, prior to the start of our work, these disorders had not been the subject of a systematic research. The aim of the study was to identify, clinically characterize and molecular genetically analyse Czech patients with monogenic IRDs and based on the knowledge gained subsequently implement preventive and therapeutic measures to clinical practice. Material and methods: We have performed a comprehensive clinical examination, genealogical analysis and molecular genetic investigation in patients with IRDs and their family members. Detailed ocular examination included spectral domain optical coherence tomography, high-resolution fundus photography and autofluorescence imaging. DNA was isolated from venous blood samples or buccal cells. Causal variants were searched for using Sanger and massively parallel sequencing, and their pathogenicity was evaluated in the context of previously published data, bioinformatical analysis and segregation in available family members. Results: In total, 103 individuals from 76 Czech families diagnosed with IRDs were characterized and their data published. Specifically, we have described clinical and molecular genetic...Institute of Inherited Metabolic Disorders First Faculty of Medicine Charles University in PragueÚstav dědičných metabolických poruch 1.LF a VFN v Praze1. lékařská fakultaFirst Faculty of Medicin

Peripapillary microcirculation in Leber hereditary optic neuropathy

Purpose In this prospective observational comparative case series, we aimed to study the peripapillary capillary network with spectral‐domain optical coherence tomography angiography (OCT‐A) in Leber hereditary optic neuropathy (LHON). Methods Twelve eyes of six individuals, of these three males (five eyes) after clinical onset of visual impairment were imaged by OCT‐A with scans centred on optic discs. Control group consisted of 6 eyes with no visual impairment. Results The three affected individuals lost vision 6 years (at age 22 years), 2 years and 3 months (at age 26 years) and 1 year and 2 months (at age 30 years) prior to OCT‐A examination. All five affected eyes had alterations in density of the radial peripapillary microvascular network at the level of retinal nerve fibre layer, including an eye of a patient treated with idebenone that underwent almost full recovery (best corrected visual acuity 0.87). Interestingly, the other eye showed normal ocular findings 14 months after onset. Results of OCT‐A examination in this eye were unfortunately inconclusive due to a delineation error. At the level of the ganglion cell layer differences could be also noted, but only in two severely affected individuals. There were no differences between unaffected mutation carriers and control eyes. Conclusion Optical coherence tomography angiography scans confirmed that the peripapillary microvascular network is highly abnormal in eyes manifesting visual impairment due to LHON. These findings support the hypothesis that microangiopathy contributes to the development of vision loss in this mitochondrial disorder

Epidemiology and preventive measures in inherited retinal dystrophies in the Czech Republic.

Introduction: Inherited retinal diseases (IRDs) are one of the most common causes of incurable blindness in children and young adults. In the Czech Republic, prior to the start of our work, these disorders had not been the subject of a systematic research. The aim of the study was to identify, clinically characterize and molecular genetically analyse Czech patients with monogenic IRDs and based on the knowledge gained subsequently implement preventive and therapeutic measures to clinical practice. Material and methods: We have performed a comprehensive clinical examination, genealogical analysis and molecular genetic investigation in patients with IRDs and their family members. Detailed ocular examination included spectral domain optical coherence tomography, high-resolution fundus photography and autofluorescence imaging. DNA was isolated from venous blood samples or buccal cells. Causal variants were searched for using Sanger and massively parallel sequencing, and their pathogenicity was evaluated in the context of previously published data, bioinformatical analysis and segregation in available family members. Results: In total, 103 individuals from 76 Czech families diagnosed with IRDs were characterized and their data published. Specifically, we have described clinical and molecular genetic..

Modern diagnostic and therapeutic approaches in familial maculopathy with reference to North Carolina macular dystrophy

Aims. We present a familial hereditary macular dystrophy, resembling North Carolina Macular Dystrophy. In members of a family, we describe the development of diagnostic-therapeutic approaches and their impact on the prognosis of those whose vision was affected. Methods. The macular dystrophy of varying degrees of severity was diagnosed in 3 consecutive generations in different family members, both men and women. Modern therapeutic tools were used for the diagnostics. In one patient of the youngest generation, the development of secondary choroidal neovascularization (CNV) was identified and treated with an anti-VEGF (vascular endothelial growth factor) agent. DNA was isolated from venous blood and genome sequencing was performed in a proband. Results. We analysed the data of 13 members of one family of three consecutive generations. Six of them had macular dystrophy. The first were two of three siblings, a woman (73 years old) and a man (67). The offspring of the afflicted man, a female (36) and a male (80), had maculopathy. The first daughter of the woman (12) revealed findings of maculopathy but with normal electrical activity of the retina. The second girl (18), developed secondary CNV which responded well to intravitreal anti-VEGF treatment. Genetic analysis excluded mutations previously reported to be pathogenic for NCMD. Conclusion. If there is a maculopathy of unclear etiology in younger patients or in patients with unclear development or appearance, it is advisable to focus carefully on the family history and trace the occurrence of impaired vision in other family members

Case report: A rare variant m.4135T>C in the MT-ND1 gene leads to Leber hereditary optic neuropathy and altered respiratory chain supercomplexes

Leber hereditary optic neuropathy is a primary mitochondrial disease characterized by acute visual loss due to the degeneration of retinal ganglion cells. In this study, we describe a patient carrying a rare missense heteroplasmic variant in MT-ND1, NC_012920.1:m.4135T>C (p.Tyr277His) manifesting with a typical bilateral painless decrease of the visual function, triggered by physical exercise or higher ambient temperature. Functional studies in muscle and fibroblasts show that amino acid substitution Tyr277 with His leads to only a negligibly decreased level of respiratory chain complex I (CI), but the formation of supercomplexes and the activity of the enzyme are disturbed noticeably. Our data indicate that although CI is successfully assembled in the patient’s mitochondria, its function is hampered by the m.4135T>C variant, probably by stabilizing CI in its inactive form. We conclude that the m.4135T>C variant together with a combination of external factors is necessary to manifest the phenotype

Multi-omics approach dissects cis-regulatory mechanisms underlying North Carolina macular dystrophy, a retinal enhanceropathy

North Carolina macular dystrophy (NCMD) is a rare autosomal-dominant disease affecting macular development. The disease is caused by non-coding single-nucleotide variants (SNVs) in two hotspot regions near PRDM13 and by duplications in two distinct chromosomal loci, overlapping DNase I hypersensitive sites near either PRDM13 or IRX1. To unravel the mechanisms by which these variants cause disease, we first established a genome-wide multi-omics retinal database, RegRet. Integration of UMI-4C profiles we generated on adult human retina then allowed fine-mapping of the interactions of the PRDM13 and IRX1 promoters and the identification of eighteen candidate cis-regulatory elements (cCREs), the activity of which was investigated by luciferase and Xenopus enhancer assays. Next, luciferase assays showed that the non-coding SNVs located in the two hotspot regions of PRDM13 affect cCRE activity, including two NCMD-associated non-coding SNVs that we identified herein. Interestingly, the cCRE containing one of these SNVs was shown to interact with the PRDM13 promoter, demonstrated in vivo activity in Xenopus, and is active at the developmental stage when progenitor cells of the central retina exit mitosis, suggesting that this region is a PRDM13 enhancer. Finally, mining of single-cell transcriptional data of embryonic and adult retina revealed the highest expression of PRDM13 and IRX1 when amacrine cells start to synapse with retinal ganglion cells, supporting the hypothesis that altered PRDM13 or IRX1 expression impairs interactions between these cells during retinogenesis. Overall, this study provides insight into the cis-regulatory mechanisms of NCMD and supports that this condition is a retinal enhanceropathy