AAV-mediated RLBP1 gene therapy improves the rate of dark adaptation in Rlbp1 knockout mice.

Recessive mutations in RLBP1 cause a form of retinitis pigmentosa in which the retina, before its degeneration leads to blindness, abnormally slowly recovers sensitivity after exposure to light. To develop a potential gene therapy for this condition, we tested multiple recombinant adeno-associated vectors (rAAVs) composed of different promoters, capsid serotypes, and genome conformations. We generated rAAVs in which sequences from the promoters of the human RLBP1, RPE65, or BEST1 genes drove the expression of a reporter gene (green fluorescent protein).

Next generation sequencing of pooled samples reveals new SNRNP200 mutations associated with retinitis pigmentosa.

The gene SNRNP200 is composed of 45 exons and encodes a protein essential for pre-mRNA splicing, the 200 kDa helicase hBrr2. Two mutations in SNRNP200 have recently been associated with autosomal dominant retinitis pigmentosa (adRP), a retinal degenerative disease, in two families from China. In this work we analyzed the entire 35-Kb SNRNP200 genomic region in a cohort of 96 unrelated North American patients with adRP.

Novel mutations in the long isoform of the USH2A gene in patients with Usher syndrome type II or non-syndromic retinitis pigmentosa.

Background: Usher syndrome type II (USH2) is an autosomal recessive disorder characterised by retinitis pigmentosa (RP) and mild to moderate sensorineural hearing loss. Mutations in the USH2A gene are the most common cause of USH2 and are also a cause of some forms of RP without hearing loss (ie, non-syndromic RP). The USH2A gene was initially identified as a transcript comprised of 21 exons but subsequently a longer isoform containing 72 exons was identified.

A single-base substitution within an intronic repetitive element causes dominant retinitis pigmentosa with reduced penetrance.

We report the study of a large American family displaying autosomal dominant retinitis pigmentosa with reduced penetrance, a form of hereditary retinal degeneration. Although the inheritance pattern and previous linkage mapping pointed to the involvement of the PRPF31 gene, extensive screening of all its exons and their boundaries failed in the past to reveal any mutation. In this work, we sequenced the entire PRPF31 genomic region by both the classical Sanger method and ultrahigh throughput (UHT) sequencing.

Search for a correlation between telomere length and severity of retinitis pigmentosa due to the dominant rhodopsin Pro23His mutation.

Purpose: Great variation exists in the age of onset of symptoms and the severity of disease at a given age in patients with retinitis pigmentosa (RP). The final pathway for this disease may involve apoptotic photoreceptor cell death. Telomere length is associated with biologic aging, senescence, and apoptosis.

A homozygous missense mutation in the IRBP gene (RBP3) associated with autosomal recessive retinitis pigmentosa.

Purpose: Interphotoreceptor retinoid-binding protein (IRBP) has been considered essential for normal rod and cone function, as it mediates the transport of retinoids between the photoreceptors and the retinal pigment epithelium. This study was performed to determine whether mutations in the IRBP gene (RBP3) are associated with photoreceptor degeneration.

Methods: A consanguineous family was ascertained in which four children had autosomal recessive retinitis pigmentosa (RP).

Insights from retinitis pigmentosa into the roles of isocitrate dehydrogenases in the Krebs cycle.

Here we describe two families with retinitis pigmentosa, a hereditary neurodegeneration of rod and cone photoreceptors in the retina. Affected family members were homozygous for loss-of-function mutations in IDH3B, encoding the beta-subunit of NAD-specific isocitrate dehydrogenase (NAD-IDH, or IDH3), which is believed to catalyze the oxidation of isocitrate to alpha-ketoglutarate in the citric acid cycle. Cells from affected individuals had a substantial reduction of NAD-IDH activity, with about a 300-fold increase in the K(m) for NAD.

Disease course in patients with autosomal recessive retinitis pigmentosa due to the USH2A gene.

Purpose: To estimate the mean rates of ocular function loss in patients with autosomal recessive retinitis pigmentosa due to USH2A mutations.

Methods: In 125 patients with USH2A mutations, longitudinal regression was used to estimate mean rates of change in Snellen visual acuity, Goldmann visual field area (V4e white test light), and 30-Hz (cone) full-field electroretinogram amplitude. These rates were compared with those of previously studied cohorts with dominant retinitis pigmentosa due to RHO mutations and with X-linked retinitis pigmentosa due to RPGR mutations.

Novel mutations in the KCNV2 gene in patients with cone dystrophy and a supernormal rod electroretinogram.

Purpose: To identify mutations in KCNV2 in patients with a form of cone dystrophy characterized by a supernormal rod electroretinogram (ERG).

Methods: The 2 exons and flanking intron DNA of KCNV2 from 8 unrelated patients were PCR amplified and sequenced.

Results: We found 1 frameshift, 2 nonsense, 1 non-stop, and 6 missense mutations.

Low prevalence of lecithin retinol acyltransferase mutations in patients with Leber congenital amaurosis and autosomal recessive retinitis pigmentosa.

Purpose: To determine the the prevalence of pathogenic mutations in the gene encoding lecithin retinol acyltransferase (LRAT) in patients from North America with either Leber congenital amaurosis (LCA) or autosomal recessive retinitis pigmentosa (ARRP).

Methods: Exon 1, exon 2, and the coding region of exon 3 of LRAT were PCR-amplified and directly sequenced from the leukocyte DNA of 82 unrelated patients with LCA and 190 unrelated patients with ARRP.

Results: One isocoding change was found in this screen of LRAT (Glu114 GAG>GAA; c.

A screen for mutations in the transducin gene GNB1 in patients with autosomal dominant retinitis pigmentosa.

Purpose: To search for mutations in the GNB1 gene (coding for the transducin beta1-subunit protein) in patients with autosomal dominant retinitis pigmentosa.

Methods: We screened 185 unrelated patients with autosomal dominant retinitis pigmentosa (ADRP) using direct genomic sequencing of the three non-coding exons and 9 coding exons, along with immediately flanking intron DNA.

Results: We found 2 polymorphisms, one in intron 1 with a minor allele frequency of 24%, and one in intron 6 with a minor allele frequency of 12% among the 185 patients.

Variation in retinitis pigmentosa-11 (PRPF31 or RP11) gene expression between symptomatic and asymptomatic patients with dominant RP11 mutations.

Dominant mutations in the mRNA splicing factor gene PRPF31 (RP11) cause retinitis pigmentosa with reduced penetrance. We studied the expression of RP11 in lymphoblast cell lines from 10 patients, including three who were clinically asymptomatic, with six distinct RP11 mutations. Five of the six mutations were characterized and all five created premature nonsense codons or eliminated the normal initiation codon.

Clinical phenotype in a Swedish family with a mutation in the IMPDH1 gene.

Purpose: Mutations in the inosine monophosphate dehydrogenase 1 gene (IMPDH1) have recently been discovered to cause a form of autosomal dominant retinitis pigmentosa (adRP). Such mutations are estimated to account for approximately 2-5% of the adRP cases among Americans of European origin and Europeans. Aiming towards an understanding of the molecular background of retinitis pigmentosa, this paper describes the phenotype of a Swedish family with a mutation in IMPDH1.

Screen of the IMPDH1 gene among patients with dominant retinitis pigmentosa and clinical features associated with the most common mutation, Asp226Asn.

Purpose: To determine the frequency of mutations in IMPDH1 among patients with autosomal dominant retinitis pigmentosa (RP), to characterize the clinical features of patients with the Asp226Asn mutation in this gene, and to compare these features with those found among patients with selected dominant mutations in other RP genes.

Methods: The coding sequence and the adjacent flanking intron sequences of all 14 coding exons were sequenced in 183 unrelated patients with dominant RP. The clinical findings evaluated included visual acuity, refractive error, visual field area measured with the Goldmann perimeter, final dark-adaptation threshold, full-field electroretinogram (ERG) amplitudes, cataract, and funduscopic bone spicule pigmentation.

Night blindness and abnormal cone electroretinogram ON responses in patients with mutations in the GRM6 gene encoding mGluR6.

We report three unrelated patients with mutations in the GRM6 gene that normally encodes the glutamate receptor mGluR6. This neurotransmitter receptor has been shown previously to be present only in the synapses of the ON bipolar cell dendrites, and it mediates synaptic transmission from rod and cone photoreceptors to this type of second-order neuron. Despite the synaptic defect, best visual acuities were normal or only moderately reduced (20/15 to 20/40).

Mutated alleles of the rod and cone Na-Ca+K-exchanger genes in patients with retinal diseases.

Purpose: To study the possible involvement of the rod (SLC24A1) and cone (SLC24A2) Na-Ca+K exchanger (NCKX) genes in retinal diseases.

Methods: DNA was collected from unrelated patients with retinal disease, mainly from North America. A human genomic library was screened with the cone NCKX cDNA, and hybridizing clones were sequenced to determine the genomic organization of the SLC24A2 gene.