PURPOSE: We observed four individuals in two unrelated but consanguineous families from Portugal and Brazil affected by early-onset retinal degeneration, sensorineural hearing loss, microcephaly, intellectual disability, and skeletal dysplasia with scoliosis and short stature. The phenotype precisely matched that of an individual of Azorean descent published in 1986 by Liberfarb and coworkers. METHODS: Patients underwent specialized clinical examinations (including ophthalmological, audiological, orthopedic, radiological, and developmental assessment). Exome and targeted sequencing was performed on selected individuals. Minigene constructs were assessed by quantitative polymerase chain reaction (qPCR) and Sanger sequencing. RESULTS: Affected individuals shared a 3.36-Mb region of autozygosity on chromosome 22q12.2, including a 10-bp deletion (NM_014338.3:c.904-12_904-3delCTATCACCAC), immediately upstream of the last exon of the PISD (phosphatidylserine decarboxylase) gene. Sequencing of PISD from paraffin-embedded tissue from the 1986 case revealed the identical homozygous variant. In HEK293T cells, this variant led to aberrant splicing of PISD transcripts. CONCLUSION: We have identified the genetic etiology of the Liberfarb syndrome, affecting brain, eye, ear, bone, and connective tissue. Our work documents the migration of a rare Portuguese founder variant to two continents and highlights the link between phospholipid metabolism and bone formation, sensory defects, and cerebral development, while raising the possibility of therapeutic phospholipid replacement.
Several groups have reported the results of clinical trials of gene augmentation therapy for Leber congenital amaurosis (LCA) because of mutations in the RPE65 gene. These studies have used subretinal injection of adeno-associated virus (AAV) vectors to deliver the human RPE65 cDNA to the retinal pigment epithelial (RPE) cells of the treated eyes. In all of the studies reported to date, this approach has been shown to be both safe and effective. The successful clinical trials of gene augmentation therapy for retinal degeneration caused by mutations in the RPE65 gene sets the stage for broad application of gene therapy to treat retinal degenerative disorders.
Pollack S, Igo RP, Jensen RA, Christiansen M, Li X, Cheng C-Y, Ng MCY, Smith AV, Rossin EJ, Segrè AV, Davoudi S, Tan GS, Chen Y-DI, Kuo JZ, Dimitrov LM, Stanwyck LK, Meng W, Hosseini MS, Imamura M, Nousome D, Kim J, Hai Y, Jia Y, Ahn J, Leong A, Shah K, Park KH, Guo X, Ipp E, Taylor KD, Adler SG, Sedor JR, Freedman BI, Family Investigation of Nephropathy and Diabetes-Eye Research Group DCCT/EDICRG, Lee I-T, Sheu WH-H, Kubo M, Takahashi A, Hadjadj S, Marre M, Tregouet D-A, McKean-Cowdin R, Varma R, McCarthy MI, Groop L, Ahlqvist E, Lyssenko V, Agardh E, Morris A, Doney ASF, Colhoun HM, Toppila I, Sandholm N, Groop P-H, Maeda S, Hanis CL, Penman A, Chen CJ, Hancock H, Mitchell P, Craig JE, Chew EY, Paterson AD, Grassi MA, Palmer C, Bowden DW, Yaspan BL, Siscovick D, Cotch MF, Wang JJ, Burdon KP, Wong TY, Klein BEK, Klein R, Rotter JI, Iyengar SK, Price AL, Sobrin L. Multiethnic Genome-Wide Association Study of Diabetic Retinopathy Using Liability Threshold Modeling of Duration of Diabetes and Glycemic Control. Diabetes 2019;68(2):441-456.Abstract
To identify genetic variants associated with diabetic retinopathy (DR), we performed a large multiethnic genome-wide association study. Discovery included eight European cohorts ( = 3,246) and seven African American cohorts ( = 2,611). We meta-analyzed across cohorts using inverse-variance weighting, with and without liability threshold modeling of glycemic control and duration of diabetes. Variants with a value <1 × 10 were investigated in replication cohorts that included 18,545 European, 16,453 Asian, and 2,710 Hispanic subjects. After correction for multiple testing, the C allele of rs142293996 in an intron of nuclear VCP-like () was associated with DR in European discovery cohorts ( = 2.1 × 10), but did not reach genome-wide significance after meta-analysis with replication cohorts. We applied the Disease Association Protein-Protein Link Evaluator (DAPPLE) to our discovery results to test for evidence of risk being spread across underlying molecular pathways. One protein-protein interaction network built from genes in regions associated with proliferative DR was found to have significant connectivity ( = 0.0009) and corroborated with gene set enrichment analyses. These findings suggest that genetic variation in as well as variation within a protein-protein interaction network that includes genes implicated in inflammation, may influence risk for DR.
Only a small fraction of the mammalian genome codes for messenger RNAs destined to be translated into proteins, and it is generally assumed that a large portion of transcribed sequences--including introns and several classes of noncoding RNAs (ncRNAs)--do not give rise to peptide products. A systematic examination of translation and physiological regulation of ncRNAs has not been conducted. Here we use computational methods to identify the products of non-canonical translation in mouse neurons by analysing unannotated transcripts in combination with proteomic data. This study supports the existence of non-canonical translation products from both intragenic and extragenic genomic regions, including peptides derived from antisense transcripts and introns. Moreover, the studied novel translation products exhibit temporal regulation similar to that of proteins known to be involved in neuronal activity processes. These observations highlight a potentially large and complex set of biologically regulated translational events from transcripts formerly thought to lack coding potential.
Qi Q, Kilpeläinen TO, Downer MK, Tanaka T, Smith CE, Sluijs I, Sonestedt E, Chu AY, Renström F, Lin X, Angquist LH, Huang J, Liu Z, Li Y, Asif Ali M, Xu M, Ahluwalia TS, Boer JMA, Chen P, Daimon M, Eriksson J, Perola M, Friedlander Y, Gao Y-T, Heppe DHM, Holloway JW, Houston DK, Kanoni S, Kim Y-M, Laaksonen MA, Jääskeläinen T, Lee NR, Lehtimäki T, Lemaitre RN, Lu W, Luben RN, Manichaikul A, Männistö S, Marques-Vidal P, Monda KL, Ngwa JS, Perusse L, van Rooij FJA, Xiang Y-B, Wen W, Wojczynski MK, Zhu J, Borecki IB, Bouchard C, Cai Q, Cooper C, Dedoussis GV, Deloukas P, Ferrucci L, Forouhi NG, Hansen T, Christiansen L, Hofman A, Johansson I, Jørgensen T, Karasawa S, Khaw K-T, Kim M-K, Kristiansson K, Li H, Lin X, Liu Y, Lohman KK, Long J, Mikkilä V, Mozaffarian D, North K, Pedersen O, Raitakari O, Rissanen H, Tuomilehto J, van der Schouw YT, Uitterlinden AG, Zillikens CM, Franco OH, Shyong Tai E, Ou Shu X, Siscovick DS, Toft U, Verschuren MWM, Vollenweider P, Wareham NJ, Witteman JCM, Zheng W, Ridker PM, Kang JH, Liang L, Jensen MK, Curhan GC, Pasquale LR, Hunter DJ, Mohlke KL, Uusitupa M, Cupples AL, Rankinen T, Orho-Melander M, Wang T, Chasman DI, Franks PW, Sørensen TIA, Hu FB, Loos RJF, Nettleton JA, Qi L. FTO genetic variants, dietary intake and body mass index: insights from 177 330 individuals. Hum Mol Genet 2014;23(25):6961-72.Abstract
FTO is the strongest known genetic susceptibility locus for obesity. Experimental studies in animals suggest the potential roles of FTO in regulating food intake. The interactive relation among FTO variants, dietary intake and body mass index (BMI) is complex and results from previous often small-scale studies in humans are highly inconsistent. We performed large-scale analyses based on data from 177 330 adults (154 439 Whites, 5776 African Americans and 17 115 Asians) from 40 studies to examine: (i) the association between the FTO-rs9939609 variant (or a proxy single-nucleotide polymorphism) and total energy and macronutrient intake and (ii) the interaction between the FTO variant and dietary intake on BMI. The minor allele (A-allele) of the FTO-rs9939609 variant was associated with higher BMI in Whites (effect per allele = 0.34 [0.31, 0.37] kg/m(2), P = 1.9 × 10(-105)), and all participants (0.30 [0.30, 0.35] kg/m(2), P = 3.6 × 10(-107)). The BMI-increasing allele of the FTO variant showed a significant association with higher dietary protein intake (effect per allele = 0.08 [0.06, 0.10] %, P = 2.4 × 10(-16)), and relative weak associations with lower total energy intake (-6.4 [-10.1, -2.6] kcal/day, P = 0.001) and lower dietary carbohydrate intake (-0.07 [-0.11, -0.02] %, P = 0.004). The associations with protein (P = 7.5 × 10(-9)) and total energy (P = 0.002) were attenuated but remained significant after adjustment for BMI. We did not find significant interactions between the FTO variant and dietary intake of total energy, protein, carbohydrate or fat on BMI. Our findings suggest a positive association between the BMI-increasing allele of FTO variant and higher dietary protein intake and offer insight into potential link between FTO, dietary protein intake and adiposity.
Human adenoviruses (HAdVs) shut down host cellular cap-dependent mRNA translation while initiating the translation of viral late mRNAs in a cap-independent manner. HAdV 5' untranslated regions (5'UTRs) are crucial for cap-independent initiation, and influence mRNA localization and stability. However, HAdV translational regulation remains relatively uncharacterized. The HAdV tripartite leader (TPL), composed of three introns (TPL 1-3), is critical to the translation of HAdV late mRNA. Herein, we annotated and analyzed 72 HAdV genotypes for the HAdV TPL and another previously described leader, the i-leader. Using HAdV species D, type 37 (HAdV-D37), we show by reverse transcription PCR and Sanger sequencing that mRNAs of the HAdV-D37 E3 transcription unit are spliced to the TPL. We also identified a polycistronic mRNA for RID-α and RID-β. Analysis of the i-leader revealed a potential open reading frame within the leader sequence and the termination of this potential protein in TPL3. A potential new leader embedded within the E3 region was also detected and tentatively named the j-leader. These results suggest an underappreciated complexity of post-transcriptional regulation, and the importance of HAdV 5'UTRs for precisely coordinated viral protein expression along the path from genotype to phenotype.
The recent emergence of highly virulent human adenoviruses (HAdVs) with new tissue tropisms underscores the need to determine their ontogeny. Here we report complete high quality genome sequences and analyses for all the previously unsequenced HAdV serotypes (n = 20) within HAdV species D. Analysis of nucleotide sequence variability for these in conjunction with another 40 HAdV prototypes, comprising all seven HAdV species, confirmed the uniquely hypervariable regions within species. The mutation rate among HAdV-Ds was low when compared to other HAdV species. Homologous recombination was identified in at least two of five examined hypervariable regions for every virus, suggesting the evolution of HAdV-Ds has been highly dependent on homologous recombination. Patterns of alternating GC and AT rich motifs correlated well with hypervariable region recombination sites across the HAdV-D genomes, suggesting foci of DNA instability lead to formulaic patterns of homologous recombination and confer agility to adenovirus evolution.
Mutations in have been implicated in retinitis pigmentosa, a blinding disease caused by degeneration of rod photoreceptors. The disease mechanism in the majority of cases is haploinsufficiency. Crucially, attempts at generation of animal models of disease have proved unsuccessful, yielding animals with a visual phenotype that does not mirror human disease. This suggests that, in these animals, the transcriptional regulation of is different to humans and compared to other species. Study of the evolution of the core promoter has important implications for our understanding of human disease, as disease phenotype is modified by differentially expressed alleles in the population. lies in a head-to-head arrangement with , a gene involved in cellular apoptosis. The two genes were shown to share common regulatory elements in the human genome. In this study, the core promoters of and were characterised by dual-luciferase reporter assay using genomic DNA from the green monkey, domestic dog and house mouse. It was found that the core promoters were conserved between human and monkey. In dog, the core promoter was conserved, but different gene architecture meant the gene was controlled by a long-range promoter lying some 2000bp from the transcription start site. There was very low level of conservation (<20%) of the 5' region between mouse and human. It was shown that mouse populations did not show variable expression levels, revealing a potential explanation for the lack of phenotype observed in the knock-out mouse model.
Understanding the molecular composition of pathogenic tissues is a critical step in understanding the pathophysiology of disease and designing therapeutics. First described in 2009, single cell RNA sequencing (scRNAseq) is a methodology whereby thousands of cells are simultaneously isolated into individual micro-environments that can be altered experimentally and the genome-wide RNA expression of each cell is captured. It has undergone significant technological improvement over the last decade and gained tremendous popularity. scRNAseq is an improvement over prior pooled RNA analyses which cannot identify the cellular composition and heterogeneity of a tissue of interest. This new approach offers new opportunity for new discovery, as tissue samples can now be sub-categorized into groups of cell types based on genome-wide gene expression in an unbiased fashion. As ophthalmologists, we are uniquely positioned to obtain pathologic samples from the eye for further study. ScRNAseq has already been applied in ophthalmology to characterize retinal tissue, and it may offer the key to understanding various pathological processes in the future.
Osteogenesis imperfecta comprises a rare group of genetic disorders caused by abnormal collagen that results in increased bone fragility and other sequelae. We describe a 37-year-old woman with osteogenesis imperfecta in whom two full-thickness scleral perforations were created by adjacent teeth of 0.5 mm forceps during traction testing while undergoing routine strabismus surgery. This case reviews the ocular findings of osteogenesis imperfecta and highlights the potential risk of ocular surgical complications in these patients.
Pathogenic variants in INPP5E cause Joubert syndrome (JBTS), a ciliopathy with retinal involvement. However, despite sporadic cases in large cohort sequencing studies, a clear association with non-syndromic inherited retinal degenerations (IRDs) has not been made. We validate this association by reporting 16 non-syndromic IRD patients from ten families with bi-allelic mutations in INPP5E. Additional two patients showed early onset IRD with limited JBTS features. Detailed phenotypic description for all probands is presented. We report 14 rare INPP5E variants, 12 of which have not been reported in previous studies. We present tertiary protein modeling and analyze all INPP5E variants for deleteriousness and phenotypic correlation. We observe that the combined impact of INPP5E variants in JBTS and non-syndromic IRD patients does not reveal a clear genotype-phenotype correlation, suggesting the involvement of genetic modifiers. Our study cements the wide phenotypic spectrum of INPP5E disease, adding proof that sequence defects in this gene can lead to early-onset non-syndromic IRD.
IMPORTANCE: Total ophthalmoplegia can result from ryanodine receptor 1 (RYR1) mutations without overt associated skeletal myopathy. Patients carrying RYR1 mutations are at high risk of developing malignant hyperthermia. Ophthalmologists should be familiar with these important clinical associations. OBJECTIVE: To determine the genetic cause of congenital ptosis, ophthalmoplegia, facial paralysis, and mild hypotonia segregating in 2 pedigrees diagnosed with atypical Moebius syndrome or congenital fibrosis of the extraocular muscles. DESIGN, SETTING, AND PARTICIPANTS: Clinical data including medical and family histories were collected at research laboratories at Boston Children's Hospital and Jules Stein Eye Institute (Engle and Demer labs) for affected and unaffected family members from 2 pedigrees in which patients presented with total ophthalmoplegia, facial weakness, and myopathy. INTERVENTION: Homozygosity mapping and whole-exome sequencing were conducted to identify causative mutations in affected family members. Histories, physical examinations, and clinical data were reviewed. MAIN OUTCOME AND MEASURE: Mutations in RYR1. RESULTS: Missense mutations resulting in 2 homozygous RYR1 amino acid substitutions (E989G and R3772W) and 2 compound heterozygous RYR1 substitutions (H283R and R3772W) were identified in a consanguineous and a nonconsanguineous pedigree, respectively. Orbital magnetic resonance imaging revealed marked hypoplasia of extraocular muscles and intraorbital cranial nerves. Skeletal muscle biopsy specimens revealed nonspecific myopathic changes. Clinically, the patients' ophthalmoplegia and facial weakness were far more significant than their hypotonia and limb weakness and were accompanied by an unrecognized susceptibility to malignant hyperthermia. CONCLUSIONS AND RELEVANCE: Affected children presenting with severe congenital ophthalmoplegia and facial weakness in the setting of only mild skeletal myopathy harbored recessive mutations in RYR1, encoding the ryanodine receptor 1, and were susceptible to malignant hyperthermia. While ophthalmoplegia occurs rarely in RYR1-related myopathies, these children were atypical because they lacked significant weakness, respiratory insufficiency, or scoliosis. RYR1-associated myopathies should be included in the differential diagnosis of congenital ophthalmoplegia and facial weakness, even without clinical skeletal myopathy. These patients should also be considered susceptible to malignant hyperthermia, a life-threatening anesthetic complication avoidable if anticipated presurgically.
Circadian clocks regulate multiple physiological processes in the eye, but their requirement for retinal health remains unclear. We previously showed that Drosophila homologs of spliceosome proteins implicated in human retinitis pigmentosa (RP), the most common genetically inherited cause of blindness, have a role in the brain circadian clock. In this study, we report circadian phenotypes in murine models of RP. We found that mice carrying a homozygous H2309P mutation in () display a lengthened period of the circadian wheel-running activity rhythm. We show also that the daily cycling of circadian gene expression is dampened in the retina of H2309P mice. Surprisingly, molecular rhythms are intact in the eye cup, which includes the retinal pigment epithelium (RPE), even though the RPE is thought to be the primary tissue affected in this form of RP. Downregulation of , another RNA splicing factor implicated in RP, leads to period lengthening in a human cell culture model. The period of circadian bioluminescence in primary fibroblasts of human RP patients is not significantly altered. Together, these studies link a prominent retinal disorder to circadian deficits, which could contribute to disease pathology.
Genes within the E3 transcription unit of human adenoviruses modulate host immune responses to infection. A comprehensive genomics and bioinformatics analysis of the E3 transcription unit for 38 viruses within human adenovirus species D (HAdV-D) revealed distinct and surprising patterns of homologous recombination. Homologous recombination was identified in open reading frames for E3 CR1α, CR1β, and CR1γ, similar to that previously observed with genes encoding the three major structural capsid proteins, the penton base, hexon, and fiber.
The genome of human adenovirus (HAdV) D30 was sequenced in depth. Sequence assembly and analysis revealed two distinct viral sequences with identical hexon genes, which were the same as the one previously reported for HAdV-D30. However, one of the two viruses was found to be a recombinant of HAdV-D29. Exclusive reliance on serum neutralization can lead to mischaracterization of adenoviruses and miss coinfections. Whole-genome sequencing remains the gold standard for proper classification of HAdVs.
PURPOSE: To investigate whether the 2 subtypes of advanced age-related macular degeneration (AMD), choroidal neovascularization (CNV), and geographic atrophy (GA) segregate separately in families and to identify which genetic variants are associated with these 2 subtypes. DESIGN: Sibling correlation study and genome-wide association study (GWAS). PARTICIPANTS: For the sibling correlation study, 209 sibling pairs with advanced AMD were included. For the GWAS, 2594 participants with advanced AMD subtypes and 4134 controls were included. Replication cohorts included 5383 advanced AMD participants and 15 240 controls. METHODS: Participants had the AMD grade assigned based on fundus photography, examination, or both. To determine heritability of advanced AMD subtypes, a sibling correlation study was performed. For the GWAS, genome-wide genotyping was conducted and 6 036 699 single nucleotide polymorphisms (SNPs) were imputed. Then, the SNPs were analyzed with a generalized linear model controlling for genotyping platform and genetic ancestry. The most significant associations were evaluated in independent cohorts. MAIN OUTCOME MEASURES: Concordance of advanced AMD subtypes in sibling pairs and associations between SNPs with GA and CNV advanced AMD subtypes. RESULTS: The difference between the observed and expected proportion of siblings concordant for the same subtype of advanced AMD was different to a statistically significant degree (P = 4.2 × 10(-5)), meaning that in siblings of probands with CNV or GA, the same advanced subtype is more likely to develop. In the analysis comparing participants with CNV to those with GA, a statistically significant association was observed at the ARMS2/HTRA1 locus (rs10490924; odds ratio [OR], 1.47; P = 4.3 × 10(-9)), which was confirmed in the replication samples (OR, 1.38; P = 7.4 × 10(-14) for combined discovery and replication analysis). CONCLUSIONS: Whether CNV versus GA develops in a patient with AMD is determined in part by genetic variation. In this large GWAS meta-analysis and replication analysis, the ARMS2/HTRA1 locus confers increased risk for both advanced AMD subtypes, but imparts greater risk for CNV than for GA. This locus explains a small proportion of the excess sibling correlation for advanced AMD subtype. Other loci were detected with suggestive associations that differ for advanced AMD subtypes and deserve follow-up in additional studies.
ACO2 encodes aconitase 2, catalyzing the second step of the tricarboxylic acid. To date, there are only 6 reported families with 5 unique ACO2 mutations. Affected individuals can develop intellectual disability, epilepsy, brain atrophy, hypotonia, ataxia, optic atrophy, and retinal degeneration. Here, we report an 18-year-old boy with a novel ACO2 variant discovered on whole-exome sequencing. He presented with childhood-onset ataxia, impaired self-help skills comparable to severe-profound intellectual disability, intractable epilepsy, cerebellar atrophy, peripheral neuropathy, optic atrophy, and pigmentary retinopathy. His variant is the sixth unique ACO2 mutation. In addition, compared to mild cases (isolated optic atrophy) and severe cases (infantile death), our patient may be moderately affected, evident by increased survival and some preserved cognition (ability to speak full sentences and follow commands), which is a novel presentation. This case expands the disease spectrum to include increased survival with partly spared cognition.
Adeno-associated viruses (AAVs) have been employed successfully as gene therapy vectors in treating various genetic diseases for almost two decades. However, transgene packaging is usually imperfect, and developing a rapid and accurate method for measuring the proportion of DNA encapsidation is an important step for improving the downstream process of large scale vector production. In this study, we used two-dimensional class averages and three-dimensional classes, intermediate outputs in the single particle cryo-electron microscopy (cryo-EM) image reconstruction pipeline, to determine the proportion of DNA-packaged and empty capsid populations. Two different preparations of AAV3 were analyzed to estimate the minimum number of particles required to be sampled by cryo-EM in order for robust calculation of the proportion of the full versus empty capsids in any given sample. Cost analysis applied to the minimum amount of data required for a valid ratio suggests that cryo-EM is an effective approach to analyze vector preparations.
The use of viral vectors for inner ear gene therapy is receiving increased attention for treatment of genetic hearing disorders. Most animal studies to date have injected viral suspensions into neonatal ears, via the round window membrane. Achieving transduction of hair cells, or sensory neurons, throughout the cochlea has proven difficult, and no studies have been able to efficiently transduce sensory cells in adult ears while maintaining normal cochlear function. Here, we show, for the first time, successful transduction of all inner hair cells and the majority of outer hair cells in an adult cochlea via virus injection into the posterior semicircular canal. We used a "designer" AAV, AAV2/Anc80L65, in which the main capsid proteins approximate the ancestral sequence state of AAV1, 2, 8, and 9. Our injections also transduced ~10% of spiral ganglion cells and a much larger fraction of their satellite cells. In the vestibular sensory epithelia, the virus transduced large numbers of hair cells and virtually all the supporting cells, along with close to half of the vestibular ganglion cells. We conclude that this viral vector and this delivery route hold great promise for gene therapy applications in both cochlear and vestibular sense organs.