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(A) Fundus photographs showing pigment mottling and yellow-white flecks in both maculae. (B) Fluorescein angiography (FA) images showing the hyperfluorescent flecks extended to the midperipheral retina and fluorescence blocking by the pigment mottling in the mcular. (C) mfERG records showing severe depressed central waveform and significant paracentral/pereferral loss of retinal response. (D) Macular OCTs showing hyper-reflective deposits within the RPE layer and the level of the outer segments of the photoreceptors, thinning of the retinal outer layers and enhanced choroidal reflectivity associated with overlying atrophic retina.
Source publication
Stargardt disease is the most common cause of juvenile macular dystrophy. Five subjects from a two-generation Chinese family with Stargardt disease are reported in this study. All family members underwent complete ophthalmologic examinations. Patients of the family initiated the disease during childhood, developing progressively impaired central vi...
Citations
... p.Gly607Arg) in exon 13 of the ABCA4 gene. This same variant was previously found in patients with STGD 10,15 . Segregation was confirmed, as shown in Fig. 1. ...
Inherited retinal dystrophies (IRDs), displaying pronounced genetic and clinical heterogeneity, comprise of a broad range of diseases characterized by progressive retinal cell death and gradual loss of vision. By the combined use of whole exome sequencing (WES), SNP-array and WES-based homozygosity mapping, as well as directed DNA sequencing (Sanger), we have identified nine pathogenic variants in six genes (ABCA4, RPE65, MERTK, USH2A, SPATA7, TULP1) in 10 consanguineous Iranian families. Six of the nine identified variants were novel, including a putative founder mutation in ABCA4 (c.3260A>G, p.Glu1087Gly), detected in two families from Northeastern Iran. Our findings provide additional information to the molecular pathology of IRDs in Iran, hopefully contributing to better genetic counselling and patient management in the respective families from this country.
... In addition, P06 harboured a heterozygous mutation (NM_000350.3, ABCA4, c.2424C [ G, p. Y808*) (Fig. 6e), this mutation has previously been reported [32], and the results showed that the patient inherited the mutation c.2424C [ G from his father (Fig. 6f). ...
PurposeTo investigate complex and different phenotypes in seven Chinese patients diagnosed with Bardet–Biedl syndrome (BBS) and carrying pathogenic mutations.Methods
Seven unrelated BBS patients were enrolled. Their medical and ophthalmic histories were reviewed, and comprehensive clinical examinations, such as fundus photography, optical coherence tomography, and medical imaging, were performed. A specific hereditary eye disease enrichment panel based on exome-capture technology was used to collect and amplify the protein-coding regions of 441 targeted hereditary eye disease genes, followed by high-throughput sequencing using the Illumina HiSeq platform.ResultsAll patients exhibited the primary clinical phenotype of BBS. Seven BBS mutations were found in five patients (BBS7 in two patients, BBS10 in two patients, BBS12 in one patient), for a detection rate of 71% (5/7). The ratio of novel to known BBS mutations was 5:2.Conclusions
This study showed the phenotypic and genotypic spectrum of BBS patients from China, and the findings underscore the importance of obtaining comprehensive clinical observations and molecular analyses for ciliopathies.
... More recently, exons and splice sites have been sequenced using an amplicon tagging protocol (Zernant et al. 2011;Sciezynska et al. 2016), array-based hybridization (Schulz et al. 2017), targeted gene-panel sequencing (Consugar et al. 2015) or whole exome sequencing (Ortube et al. 2014;Zhou et al. 2014;Bryant et al. 2018). Sequence analysis of the entire 128-kb gene and up-and downstream DNA segments was performed using next-generation sequencing platforms after enrichment of ABCA4 sequences using Raindance microdroplet-PCR target enrichment or Illumina TruSeq Custom Amplicon target enrichment (Zernant et al. 2014), Haloplex-based sequence enrichment Sangermano et al. 2019), or WGS (Carss et al. 2017;Sangermano et al. 2019). ...
Missing heritability in human diseases represents a major challenge, and this is particularly true for ABCA4-associated Stargardt disease (STGD1). We aimed to elucidate the genomic and transcriptomic variation in 1054 unsolved STGD and STGD-like probands.
Sequencing of the complete 128-kb ABCA4 gene was performed using single-molecule molecular inversion probes (smMIPs), based on a semiautomated and cost-effective method. Structural variants (SVs) were identified using relative read coverage analyses and putative splice defects were studied using in vitro assays.
In 448 biallelic probands 14 known and 13 novel deep-intronic variants were found, resulting in pseudoexon (PE) insertions or exon elongations in 105 alleles. Intriguingly, intron 13 variants c.1938-621G>A and c.1938-514G>A resulted in dual PE insertions consisting of the same upstream, but different downstream PEs. The intron 44 variant c.6148-84A>T resulted in two PE insertions and flanking exon deletions. Eleven distinct large deletions were found, two of which contained small inverted segments. Uniparental isodisomy of chromosome 1 was identified in one proband.
Deep sequencing of ABCA4 and midigene-based splice assays allowed the identification of SVs and causal deep-intronic variants in 25% of biallelic STGD1 cases, which represents a model study that can be applied to other inherited diseases.
... More recently, exons and splice sites have been sequenced using an amplicon tagging protocol (Zernant et al. 2011;Sciezynska et al. 2016), array-based hybridization (Schulz et al. 2017), targeted gene-panel sequencing (Consugar et al. 2015) or whole exome sequencing (Ortube et al. 2014;Zhou et al. 2014;Bryant et al. 2018). Sequence analysis of the entire 128-kb gene and up-and downstream DNA segments was performed using next-generation sequencing platforms after enrichment of ABCA4 sequences using Raindance microdroplet-PCR target enrichment or Illumina TruSeq Custom Amplicon target enrichment (Zernant et al. 2014), Haloplex-based sequence enrichment Sangermano et al. 2019), or WGS (Carss et al. 2017;Sangermano et al. 2019). ...
Missing heritability in human diseases represents a major challenge. Although whole-genome sequencing enables the analysis of coding and non-coding sequences, substantial costs and data storage requirements hamper its large-scale use to (re)sequence genes in genetically unsolved cases. The ABCA4 gene implicated in Stargardt disease (STGD1) has been studied extensively for 22 years, but thousands of cases remained unsolved. Therefore, single molecule molecular inversion probes were designed that enabled an automated and cost-effective sequence analysis of the complete 128-kb ABCA4 gene. Analysis of 1,054 unsolved STGD and STGD-like probands resulted in bi-allelic variations in 448 probands. Twenty-seven different causal deep-intronic variants were identified in 117 alleles. Based on in vitro splice assays, the 13 novel causal deep-intronic variants were found to result in pseudo-exon (PE) insertions (n=10) or exon elongations (n=3). Intriguingly, intron 13 variants c.1938-621G>A and c.1938-514G>A resulted in dual PE insertions consisting of the same upstream, but different downstream PEs. The intron 44 variant c.6148-84A>T resulted in two PE insertions that were accompanied by flanking exon deletions. Structural variant analysis revealed 11 distinct deletions, two of which contained small inverted segments. Uniparental isodisomy of chromosome 1 was identified in one proband. Integrated complete gene sequencing combined with transcript analysis, identified pathogenic deep-intronic and structural variants in 26% of bi-allelic cases not solved previously by sequencing of coding regions. This strategy serves as a model study that can be applied to other inherited diseases in which only one or a few genes are involved in the majority of cases.
... The proband's parents had a consanguineous marriage, and they were each heterozygous for c.2426 a>c, which was also found in members V:1, iV:1 and iii:3 (Table i). as previously reported, laminin aG-like domain is predicted to affect interactions among proteins, calcium binding, and protein folding (26). This mutation introduces a substitution of glutanine to threonine, which may dramatically affect the function of the second laminin aG-like domain of the crB1 protein (PolyPhen2 scores ~0.824). ...
Retinitis pigmentosa (RP) is a leading cause of inherited blindness characterized by progressive loss of retinal photoreceptor cells. The present study aimed to identify the causative gene mutations in two Chinese families with autosomal recessive retinitis pigmentosa (arRP). Two Chinese consanguineous arRP families (RP‑2284 and RP‑2360) were recruited in this study, involving totally three affected and 25 unaffected members. All the affected members underwent a complete ophthalmic examination, including fundus photography, multifocal electroretinography (ERG) and full field ERG. Exome sequencing was performed on the three RP patients in the two families, followed by direct Sanger sequencing in all the family members and in 1,260 unrelated controls for validation of the mutations identified. Two homozygous missense mutations in the crumbs homolog 1 (CRB1) gene, which is known to cause severe retinal dystrophies, were found to be related to the phenotype of the two arRP families. The homozygous missense mutation c.1997 T>A in CRB1 was detected in two patients in the RP‑2284 family. The proband in the RP‑2360 family was the only RP patient and was found to carry the novel homozygous missense mutation c.2426 A>C in CRB1. The two mutations were heterozygous or absent in the other healthy family members, and they were absent in the 1,260 controls. The amino acid changes in the CRB1 protein affected by the two mutations were predicted to be damaging by Polyohen‑2. Our study reported two CRB1 mutations causing arRP in two Chinese families, which expands the CRB1 mutation spectrum of RP in the Chinese population and emphasizes the causative role of CRB1 in RP.
... The sequenced sample was prepared according to the Illumina protocols of Sure Select Target Enrichment System Capture Process. Exome sequencing analysis was performed as described previously [14]. The peripheral blood DNA samples of 268 patients with sporadic FSGS were sequenced by next-generation sequencing. ...
Background:
Focal segmental glomerulosclerosis (FSGS) is still one of the common causes of refractory nephrotic syndrome. Nephrin, encoded by podocyte-specific NPHS1 gene, participated in the pathogenesis of FSGS. The sites of NPHS1 mutations in FSGS is not clarified very well. In this study, we investigated the specific mutations of NPHS1 gene in Chinese patients with sporadic FSGS.
Methods:
A total of 309 patients with sporadic FSGS were collected and screened for NPHS1 mutations by second-generation sequencing. The variants were compared with those extracted from 2504 healthy controls in the 1000 Genomes Project. The possible pathogenic roles of missense variants were predicted by three different software. We also compared these candidate causal mutations with those summarized from the previous studies.
Results:
Thirty-two genetic mutations of NPHS1 gene were identified in FSGS patients, including 12 synonymous mutations, 17 missense mutations, 1 splicing mutation, and 2 intron mutations, of which c.G3315A (p.S1105S) was the most common variant (261/309). A novel missense mutation c.G2638 T (p.V880F) and a novel splicing mutation 35830957 C > T were identified in FSGS patients. The frequencies of the four synonymous mutations (c.C294T [p.I98I], c.C2223T [p.T741 T], c.C2289T [p.V763 V], c.G3315A [p.S1105S]) were much higher in FSGS patients than in controls. The frequencies of the four missense mutations (c.G349A [p.E117K], c.G1339A [p.E447K], c.G1802C [p.G601A], c.C2398T [p.R800C]) were much higher and one (c.A3230G [p.N1077S]) was lower in FSGS patients than in controls. Five missense mutations, c.C616A (p.P206T), c.G1802C (p.G601A), c.C2309T (p.P770L), c.G2869C (p.V957 L), and c.C3274T (p.R1092C), were predicted to be pathogenic mutations by software analysis.
Conclusions:
NPHS1 gene mutations were quite common in sporadic FSGS patients. We strongly recommend mutation analysis of the NPHS1 gene in the clinical management of FSGS patients.
... Compound heterozygous variants p.Y808X and p.G607R of ATP binding cassette, sub-family A (ABC1), member 4 (ABCA4) gene, which encodes ABCA4 protein, a member of ATP-binding cassette (ABC) transport superfamily were successfully identified as causative mutations for SD. Findings helped provide one more novel ABCA4 mutation in Chinese with SD [118] . Uveal Melanoma Uveal melanoma (UM) is characterized by an uncontrolled proliferation in a clonal fashion because of genetic and epigenetic alterations. ...
Past 25y have witnessed an exponential increase in knowledge and understanding of ocular diseases and their respective genetic underpinnings. As a result, scientists have mapped many genes and their variants that can influence vision and health of our eyes. Based on these findings, it is becoming clear that an early diagnosis employing genetic testing can help evaluate patients' conditions for instituting treatment plan(s) and follow-up care to avoid vision complications later. For example, knowing family history becomes crucial for inherited eye diseases as it can benefit members in family who may have similar eye diseases or predispositions. Therefore, gathering information from an elaborate examination along with complete assessment of past medical illness by ophthalmologists followed by consultation with geneticists can help create a roadmap for making diagnosis and treatment precise and beneficial. In this review, we present an update on ocular genomic medicine that we believe has tremendous potential towards unraveling genetic implications in ocular diseases and patients' susceptibilities. We also discuss translational aspects of genetic ophthalmology and genome engineering that may help advance molecular diagnostics and therapeutics.
... With the rapid development of sequencing technology, massively parallel sequencing or next-generation sequencing (NGS) has been frequently used for genome-wide or region-wide identification of diseaserelated variants, which includes whole-genome, whole-exome, and target-region sequencing. Exome sequencing projects in Stargardt disease cohorts have shown the enormous potential and good performance of NGS in STGD genetic research and diagnosis [21][22][23][24]. ...
Purpose
Stargardt disease (STGD) is a common macular dystrophy in juveniles that is commonly inherited as an autosomal recessive trait. Mutations in five genes (ABCA4, PROM1, ELOVL4, BEST1, and PRPH2) have been reported to be associated with STGD. In the present study, we aimed to identify the pathogenic mutations in affected members in a Chinese STGD pedigree.
Methods
One patient was selected for whole-exome sequencing. Variants in five candidate genes were identified initially, followed by several filtering steps against public and private variation databases (1000Genomes, ESP6500si, ExAC, and in-house database), as well as bioinformatic analysis of the putative pathogenic roles. Sanger sequencing was used for cosegregation analysis among all members with available DNA.
Results
Two mutations in ABCA4 (NM_000350.2; c.5646G>A; p.Met1882Ile and NM_000350.2; c.3523–2A>G) were found using whole-exome sequencing. Cosegregation analysis confirmed all the affected members carried the compound heterozygous mutations while the other healthy members had at most one. The missense mutation was extremely rare in public databases and predicted to be deleterious. The splice-site mutation was absent from all public and private databases and was predicted to alter the splice pattern, resulting in an exon skip and a frameshift.
Conclusions
Using whole-exome sequencing, we found novel compound heterozygous mutations in ABCA4 in a Chinese STGD pedigree. These mutations are reported for the first time, therefore widening the mutation spectrum of Stargardt disease. The present study also illustrates the potential of whole-exome sequencing in determining the genetic cause of STGD.
... Important retinopathies include Stargardt disease (STGD1) [OMIM: 248200], Leber congenital amaurosis [OMIM: 204000], age-related macular degeneration [OMIM: 603075], and vitelliform macular dystrophy 2 [OMIM: 153700]. STGD1 is the most common (prevalence ¼ 1e5:10,000) ABCA4-associated autosomal recessive juvenile retinal macular dystrophy that leads to progressive loss of central visual function due to atrophy of the retinal pigment epithelium (RPE) and photoreceptor layer (Zhang et al., 2014;Zhou et al., 2014). Typical STGD1 is represented by the yellowish flecks in macula and mid-periphery of retina, fundus flavimaculatus, beaten-bronze macular appearance, bull's eye maculopathy, and dysfunction and death of photoreceptor cells (Birnbach et al., 1994). ...
... Six genes (ABCA4, BEST1, CRB1, ELOVL4, PROM1, and PRPH2) are associated with various forms of central retinal dystrophies and retinopathies (Zhang et al., 2014;Zhou et al., 2014). Among these genes, more than 700 mutations in the ABCA4 gene have been implemented to cause STGD1 (Fujinami et al., 2013a,b). ...
... Although genetic variations associated with STGD1 and other ABCA4-related retinopathies are reported for Chinese (Zhou et al., 2014), British (Fujinami et al., 2013a,b), Japanese (Fukui et al., 2002), Indian (Battu et al., 2015), German (Rivera et al., 2000), Spanish (Paloma et al., 2001), Hungarian (Hargitai et al., 2005), Portuguese (Maia-Lopes et al., 2009), Danish (Duno et al., 2012), Italian (Passerini et al., 2010), Turkish (Ozgul et al., 2004), Mexican (Chacon-Camacho et al., 2013), African (Roberts et al., 2012), and African-American (Utz et al., 2013) populations no report is still available for the Russian retinopathy cohort, except a few (Demenkova et al., 2014). ...
ABCA4-associated mutation screening is extensively performed in European, African, American and several other populations for various retinopathies. However, it has not been well studied in a Russian cohort. Using next-generation (325 genes inherited disease panel) and Sanger sequencing technologies for the first time we documented the spectrum of genetic variations in a Russian retinopathy cohort of 51 patients from 10 ethnic groups. We found ABCA4 variations in 70.5% cases and one case with BEST1 variation. Multiple ABCA4 variations, ABCA4+RDH12, and ABCA4+BEST1 variations are also observed and the disease severity is found proportionate to the variation burden. Ten novel ABCA4 variations are detected of which 8 belongs to non-Slavonian population. Most of the detected known variations are found in European and American Stargardt disease populations. No retinopathy causing variation is detected in 14 (27 %) cases suggesting that in this Russian retinopathies cohort the causal variants could be in genes that are not covered by our 325 gene panel. Therefore, whole genome/exome analysis is required to identify novel retinopathy associated genes and provide better disease management for this heterogeneous cohort.
... Exome sequencing was performed on DNA samples of patient IV:2 in the Chinese family RP-2236, patient II:1 in the Indian family RP-IC-90 and all of the 100 sporadic Indian patients by Axeq Technology Inc., Seoul, Korea. Each DNA samples was prepared by the Illumina protocols of Sure Select Target Enrichment System as described previously 12 . ...
Retinitis pigmentosa (RP) is a leading cause of inherited blindness characterized by progressive degeneration of the retinal photoreceptor cells. This study aims to identify genetic mutations in a Chinese family RP-2236, an Indian family RP-IC-90 and 100 sporadic Indian individuals with autosomal recessive RP (arRP). Whole exome sequencing was performed on the index patients of RP-2236, RP-IC-90 and all of the 100 sporadic Indian patients. Direct Sanger sequencing was used to validate the mutations identified. Four novel mutations and one reported mutation in the crumbs homolog 1 (CRB1) gene, which has been known to cause severe retinal dystrophies, were identified. A novel homozygous splicing mutation c.2129-1G>C was found in the three patients In family RP-2236. A homozygous point mutation p.R664C was found in RP-IC-90. A novel homozygous mutation p.G1310C was identified in patient I-44, while novel compound heterozygous mutations p.N629D and p.A593T were found in patient I-7. All mutations described above were not present in the 1000 normal controls. In conclusion, we identified four novel mutations in CRB1 in a cohort of RP patients from the Chinese and Indian populations. Our data enlarges the CRB1 mutation spectrums and may provide new target loci for RP diagnose and treatment.
