A novel GFAP frameshift variant identified in a family with optico-retinal dysplasia and vision impairment.

Gain-of-function variants in GFAP leads to protein aggregation and is the cause of the severe neurodegenerative disorder Alexander Disease (AxD), while loss of GFAP function has been considered benign. Here, we investigated a six-generation family, where multiple individuals presented with gliosis of the optic nerve head and visual impairment. Whole genome sequencing (WGS) revealed a frameshift variant in GFAP (c.

Temporal changes in incidence, prevalence and causes of childhood visual impairment - Learnings from 45 years with the National Danish Registry of Children with Visual Impairment.

Purpose: The aim of the study was to describe the temporal changes in causes and prevalence of childhood visual impairment in Denmark based on the National Danish Registry of Children with Visual Impairment (NDRCVI).

Methods: Annual reports on the NDRCVI since its establishment in 1979 were reviewed and data on the number of registered children and the causes for registration with a visual impairment were evaluated.

Results: The average annual incidence of childhood visual impairment in Denmark is 2.

Comprehensive variant spectrum of the CNGA3 gene in patients affected by achromatopsia.

Achromatopsia (ACHM) is a congenital cone photoreceptor disorder characterized by impaired color discrimination, low visual acuity, photosensitivity, and nystagmus. To date, six genes have been associated with ACHM (CNGA3, CNGB3, GNAT2, PDE6C, PDE6H, and ATF6), the majority of these being implicated in the cone phototransduction cascade. CNGA3 encodes the CNGA3 subunit of the cyclic nucleotide-gated ion channel in cone photoreceptors and is one of the major disease-associated genes for ACHM.

Oliver McFarlane syndrome: two new cases and a review of the literature.

Background: Oliver McFarlane syndrome is a rare syndrome. Clinical presentations include trichomegaly, chorioretinal degeneration, pituitary hormone deficits, and neurological manifestations. Genetic analysis has recently placed this syndrome within the group of -related disorders.

Bi-Allelic Pathogenic Variations in Including Deletions Are Associated with an Early Onset Progressive Form of Retinitis Pigmentosa.

Bi-allelic pathogenic variants in cause retinitis pigmentosa (RP). Since deletions of more than one exon have been reported repeatedly for , CNV (copy number variation) analysis of next-generation sequencing (NGS) data has proven important in molecular genetic diagnostics of . CNV analysis was performed on NGS data of 677 individuals with inherited retinal diseases (IRD) and confirmed by quantitative RT-PCR analysis.

Clinical Phenotype and Course of PDE6A-Associated Retinitis Pigmentosa Disease, Characterized in Preparation for a Gene Supplementation Trial.

Importance: Treatment trials require sound knowledge on the natural course of disease.

Objective: To assess clinical features, genetic findings, and genotype-phenotype correlations in patients with retinitis pigmentosa (RP) associated with biallelic sequence variations in the PDE6A gene in preparation for a gene supplementation trial.

Design, Setting, And Participants: This prospective, longitudinal, observational cohort study was conducted from January 2001 to December 2019 in a single center (Centre for Ophthalmology of the University of Tübingen, Germany) with patients recruited multinationally from 12 collaborating European tertiary referral centers.

A Missense Mutation in RAB28 in a Family with Cone-Rod Dystrophy and Postaxial Polydactyly Prevents Localization of RAB28 to the Primary Cilium.

Purpose: Cone-rod dystrophy (CRD) is a rare hereditary eye disorder that causes progressive degeneration of cone and rod photoreceptors. More than 30 genes, including RAB28, have been associated with CRD; however, only a few RAB28 variants have been reported to be associated with CRD. In this study, we describe two brothers with CRD and a homozygous missense variant, c.

Mutation spectrum and clinical investigation of achromatopsia patients with mutations in the GNAT2 gene.

Achromatopsia (ACHM) is a hereditary cone photoreceptor disorder characterized by the inability to discriminate colors, nystagmus, photophobia, and low-visual acuity. Six genes have been associated with this rare autosomal recessively inherited disease, including the GNAT2 gene encoding the catalytic α-subunit of the G-protein transducin which is expressed in the cone photoreceptor outer segment. Out of a cohort of 1,116 independent families diagnosed with a primary clinical diagnosis of ACHM, we identified 23 patients with ACHM from 19 independent families with likely causative mutations in GNAT2, representing 1.

Molecular genetic analysis using targeted NGS analysis of 677 individuals with retinal dystrophy.

Inherited retinal diseases (IRDs) are a common cause of visual impairment. IRD covers a set of genetically highly heterogeneous disorders with more than 150 genes associated with one or more clinical forms of IRD. Molecular genetic diagnosis has become increasingly important especially due to expanding number of gene therapy strategies under development.

Unique noncoding variants upstream of PRDM13 are associated with a spectrum of developmental retinal dystrophies including progressive bifocal chorioretinal atrophy.

The autosomal dominant progressive bifocal chorioretinal atrophy (PBCRA) disease locus has been mapped to chromosome 6q14-16.2 that overlaps the North Carolina macular dystrophy (NCMD) locus MCDR1. NCMD is a nonprogressive developmental macular dystrophy, in which variants upstream of PRDM13 have been implicated.

A pathogenic haplotype, common in Europeans, causes autosomal recessive albinism and uncovers missing heritability in OCA1.

Oculocutaneous albinism (OCA) is a genetically heterogeneous disorder. Six genes are associated with autosomal recessive OCA (TYR, OCA2, TYRP1, SLC45A2, SLC24A5 and LRMDA), and one gene, GPR143, is associated with X-linked ocular albinism (OA). Molecular genetic analysis provides a genetic diagnosis in approximately 60% of individuals with clinical OA/OCA.

Extremely hypomorphic and severe deep intronic variants in the locus result in varying Stargardt disease phenotypes.

Autosomal recessive Stargardt disease (STGD1, MIM 248200) is caused by mutations in the gene. Complete sequencing of the locus in STGD1 patients identifies two expected disease-causing alleles in ∼75% of patients and only one mutation in ∼15% of patients. Recently, many possibly pathogenic variants in deep intronic sequences of have been identified in the latter group.

Increased Mortality and Comorbidity Associated With Leber's Hereditary Optic Neuropathy: A Nationwide Cohort Study.

Purpose: Leber's hereditary optic neuropathy (LHON) is a mitochondrial genetic disease in which optic neuropathy is considered a key feature. Several other manifestations of LHON have been reported; however, only little is known of their incidence and the life expectancy in LHON patients.

Methods: This study, based on Danish nationwide health registries, included 141 patients diagnosed with LHON and 297 unaffected family members in the maternal line.

Exome Sequence Analysis of 14 Families With High Myopia.

Purpose: To identify causal gene mutations in 14 families with autosomal dominant (AD) high myopia using exome sequencing.

Methods: Select individuals from 14 large Caucasian families with high myopia were exome sequenced. Gene variants were filtered to identify potential pathogenic changes.

Choroideremia: melanopsin-mediated postillumination pupil relaxation is abnormally slow.

Purpose: To investigate the rod-cone and melanopsin pupillary light response (PLR) pathways in choroideremia.

Methods: Eight patients with choroideremia and 18 healthy age-matched controls underwent chromatic pupillometry by applying blue (463 nm) and red light (643 nm) at 100 lux intensity to the right eye while recording pupil diameters. Absolute baseline pupil size (mm), normalized maximal pupil constriction and the early and late postillumination pupillary dilation, from 0 to 10 seconds and 10 to 30 seconds after the end of illumination, respectively, were determined.

Leber hereditary optic neuropathy due to a new ND1 mutation.

We report a proband with Leber hereditary optic neuropathy (LHON), in whom we have identified a novel homoplasmic m.3,395A>G mutation in the ND1 gene. The mutation alters a highly conserved amino acid in codon 30 which previously has been associated with LHON and leads to a severe selective complex I deficiency.

Clinical Characteristics, Mutation Spectrum, and Prevalence of Åland Eye Disease/Incomplete Congenital Stationary Night Blindness in Denmark.

Purpose: To assess clinical characteristics, foveal structure, mutation spectrum, and prevalence rate of Åland eye disease (AED)/incomplete congenital stationary night blindness (iCSNB).

Methods: A retrospective survey included individuals diagnosed with AED at a national low-vision center from 1980 to 2014. A subset of affected males underwent ophthalmologic examinations including psychophysical tests, full-field electroretinography, and spectral-domain optical coherence tomography.

Usher syndrome in Denmark: mutation spectrum and some clinical observations.

Background: Usher syndrome (USH) is a genetically heterogeneous deafness-blindness syndrome, divided into three clinical subtypes: USH1, USH2 and USH3.

Methods: Mutations in 21 out of 26 investigated Danish unrelated individuals with USH were identified, using a combination of molecular diagnostic methods.

Results: Before Next Generation Sequencing (NGS) became available mutations in nine individuals (1 USH1, 7 USH2, 1 USH3) were identified by Sanger sequencing of , or or by Arrayed Primer EXtension (APEX) method.

De novo intrachromosomal gene conversion from OPN1MW to OPN1LW in the male germline results in Blue Cone Monochromacy.

X-linked cone dysfunction disorders such as Blue Cone Monochromacy and X-linked Cone Dystrophy are characterized by complete loss (of) or reduced L- and M- cone function due to defects in the OPN1LW/OPN1MW gene cluster. Here we investigated 24 affected males from 16 families with either a structurally intact gene cluster or at least one intact single (hybrid) gene but harbouring rare combinations of common SNPs in exon 3 in single or multiple OPN1LW and OPN1MW gene copies. We assessed twelve different OPN1LW/MW exon 3 haplotypes by semi-quantitative minigene splicing assay.

Prevalence and Genetics of Leber Hereditary Optic Neuropathy in the Danish Population.

Purpose: In Denmark, the occurrence of Leber hereditary optic neuropathy (LHON) has continuously been monitored since 1944. We provide here a summary of 70 years of data collection including registered lines and subjects by the end of 2012.

Methods: Affected individuals were identified from a national register of hereditary eye diseases at the National Eye Clinic (NEC), a tertiary low vision rehabilitation center for the entire Danish population.

Mutation Detection in Patients with Retinal Dystrophies Using Targeted Next Generation Sequencing.

Retinal dystrophies (RD) constitute a group of blinding diseases that are characterized by clinical variability and pronounced genetic heterogeneity. The different nonsyndromic and syndromic forms of RD can be attributed to mutations in more than 200 genes. Consequently, next generation sequencing (NGS) technologies are among the most promising approaches to identify mutations in RD.

Comprehensive genotyping reveals RPE65 as the most frequently mutated gene in Leber congenital amaurosis in Denmark.

Leber congenital amaurosis (LCA) represents the most severe form of inherited retinal dystrophies with an onset during the first year of life. Currently, 21 genes are known to be associated with LCA and recurrent mutations have been observed in AIPL1, CEP290, CRB1 and GUCY2D. In addition, sequence analysis of LRAT and RPE65 may be important in view of treatments that are emerging for patients carrying variants in these genes.