Associations between 25 hydroxyvitamin D concentration and spontaneous abortion.

BACKGROUND: Spontaneous abortion is a common complication of pregnancy that can lead to adverse physical and psychological outcomes for women. Vitamin D is reported to be associated with reproductive functions, whereas its casual effects on abortion remains unclear. MATERIALS AND METHODS: In this study, a two-sample Mendelian randomization (MR) analysis was performed to systematically assess the causal relationships between serum 25 hydroxyvitamin D [25(OH)D] concentration and the risk of spontaneous abortion. GWAS summary data of 25(OH)D were used as exposure, and data of spontaneous abortion was considered as outcome. A retrospective study was additionally conducted to verify the MR results. RESULTS: MR estimates showed that a higher 25(OH)D level was potentially associated with decreased risk of spontaneous abortion (IVW, OR = 0.98, 95%CI = 0.90-1.06; MR Egger, OR = 0.94, 95%CI = 0.84-1.05; Weighted median, OR = 0.93, 95%CI = 0.82-1.06; Weighted mode, OR = 0.93, 95%CI = 0.84-1.03), though the P-value was not statistically significant. The retrospective study also produced consistent result of Vitamin D's protective role to spontaneous abortion. The P-value was very close to statistical significance (P = 0.053). CONCLUSIONS: This study reports the potential protective role of serum 25(OH)D concentration to spontaneous abortion, suggesting that increased vitamin D levels may decrease the risk of abortion. Further larger prospective studies and/or even randomized controlled trials are needed to confirm causal relationship between vitamin D and abortion.

[Progress in Gene Polymorphisms Associated With Osteoporosis Susceptibility in Zhuang Ethnic Group in Guangxi].

The purpose of this paper is to systematically summarize the gene polymorphisms associated with osteoporosis(OP)susceptibility in Zhuang ethnic group in Guangxi.These genes mainly encode vitamin D receptor,estrogen receptor,calcitonin receptor,and adiponectin.The genotype and allele distribution frequency were compared between Zhuang ethnic group and other ethnic groups,which can clarify the existing genes and the potential gene polymorphism associated with OP in Zhuang ethnic group.The findings provide a representative solution for the subsequent research on the genes associated with OP susceptibility in ethnic minorities.

Proteome-wide analysis reveals potential therapeutic targets for Colorectal cancer: a two-sample mendelian randomization study.

BACKGROUND: Colorectal cancer (CRC) is a leading cause of cancer-related mortality, highlighting an unmet clinical need for more effective therapies. This study aims to evaluate the causal relationship between 4,489 plasma proteins and CRC to identify potential therapeutic targets for CRC. METHODS: We conducted two-sample Mendelian randomization (MR) analysis to examine the causal effects of plasma proteins on CRC. Mediation analysis was performed to assess the indirect effects of plasma proteins on CRC through associated risk factors. In addition, we conducted a phenome-wide association study using the UK Biobank dataset to examine associations between these plasma proteins and other phenotypes. RESULTS: Out of 4,489 plasma proteins, MR analysis revealed causal associations with CRC for 23 proteins, including VIMP, MICB, TNFRSF11B, C5orf38 and SLC5A8. Our findings also confirm the associations between reported risk factors and CRC. Mediation analysis identified mediating effects of proteins on CRC outcomes through risk factors. Furthermore, MR analysis identified 154 plasma proteins are causally linked to at least one CRC risk factor. CONCLUSIONS: Our study evaluated the causal relationships between plasma proteins and CRC, providing a more complete understanding of potential therapeutic targets for CRC.

A precise and efficient adenine base editor.

Adenine base editors (ABEs) are novel genome-editing tools, and their activity has been greatly enhanced by eight additional mutations, thus named ABE8e. However, elevated catalytic activity was concomitant with frequent generation of bystander mutations. This bystander effect precludes its safe applications required in human gene therapy. To develop next-generation ABEs that are both catalytically efficient and positionally precise, we performed combinatorial engineering of NG-ABE8e. We identify a novel variant (NG-ABE9e), which harbors nine mutations. NG-ABE9e exhibits robust and precise base-editing activity in human cells, with more than 7-fold bystander editing reduction at some sites, compared with NG-ABE8e. To demonstrate its practical utility, we used NG-ABE9e to correct the frequent T17M mutation in Rhodopsin for autosomal dominant retinitis pigmentosa. It reduces bystander editing by ∼4-fold while maintaining comparable efficiency. NG-ABE9e possesses substantially higher activity than NG-ABEmax and significantly lower bystander editing than NG-ABE8e in rice. Therefore, this study provides a versatile and improved adenine base editor for genome editing.

Progress in the genetics of uveitis.

Uveitis is the most common form of intraocular inflammatory disease and is a significant cause of visual impairment worldwide. Aetiologically, uveitis can also be classified into infectious uveitis and non-infectious uveitis. The common non-infectious forms of uveitis include acute anterior uveitis (AAU), Behçet's disease (BD), Vogt-Koyanagi-Harada (VKH) disease, birdshot chorioretinopathy (BSCR), sarcoid uveitis. In addition, a few monogenic autoinflammatory disorders can also cause uveitis, such as Blau Syndrome and haploinsufficiency of A20 (HA20). Although the exact pathogenesis of non-infectious uveitis is still unclear, it is well-recognised that it involves both genetic and environmental risk factors. A hallmark of uveitis is its strong associations with human leucocyte antigens (HLA). For examples, AAU, BD and BSCR are strongly associated with HLA-B27, HLA-B51, and HLA-A29, respectively. In uveitis studies, multiple GWAS have successfully been conducted and led to identification of novel susceptibility loci, for example, IL23R has been identified in BD, VKH and AAU. In this review, we summarize the latest progress on the genetic associations of both HLA and non-HLA genes with major forms of uveitis, including AAU, BD, VKH, BSCR, sarcoid uveitis, Blau Syndrome and HA20, and potential future research directions.

Periodontal disease increases the host susceptibility to COVID-19 and its severity: a Mendelian randomization study.

BACKGROUND: Emerging evidence shows that periodontal disease (PD) may increase the risk of Coronavirus disease 2019 (COVID-19) complications. Here, we undertook a two-sample Mendelian randomization (MR) study, and investigated for the first time the possible causal impact of PD on host susceptibility to COVID-19 and its severity. METHODS: Summary statistics of COVID-19 susceptibility and severity were retrieved from the COVID-19 Host Genetics Initiative and used as outcomes. Single nucleotide polymorphisms associated with PD in Genome-wide association study were included as exposure. Inverse-variance weighted (IVW) method was employed as the main approach to analyze the causal relationships between PD and COVID-19. Three additional methods were adopted, allowing the existence of horizontal pleiotropy, including MR-Egger regression, weighted median and weighted mode methods. Comprehensive sensitivity analyses were also conducted for estimating the robustness of the identified associations. RESULTS: The MR estimates showed that PD was significantly associated with significantly higher susceptibility to COVID-19 using IVW (OR = 1.024, P = 0.017, 95% CI 1.004-1.045) and weighted median method (OR = 1.029, P = 0.024, 95% CI 1.003-1.055). Furthermore, it revealed that PD was significantly linked to COVID-19 severity based on the comparison of hospitalization versus population controls (IVW, OR = 1.025, P = 0.039, 95% CI 1.001-1.049; weighted median, OR = 1.030, P = 0.027, 95% CI 1.003-1.058). No such association was observed in the cohort of highly severe cases confirmed versus those not hospitalized due to COVID-19. CONCLUSIONS: We provide evidence on the possible causality of PD accounting for the susceptibility and severity of COVID-19, highlighting the importance of oral/periodontal healthcare for general wellbeing during the pandemic and beyond.

Genetic signatures of high-altitude adaptation in Tibetans.

Indigenous Tibetan people have lived on the Tibetan Plateau for millennia. There is a long-standing question about the genetic basis of high-altitude adaptation in Tibetans. We conduct a genome-wide study of 7.3 million genotyped and imputed SNPs of 3,008 Tibetans and 7,287 non-Tibetan individuals of Eastern Asian ancestry. Using this large dataset, we detect signals of high-altitude adaptation at nine genomic loci, of which seven are unique. The alleles under natural selection at two of these loci [methylenetetrahydrofolate reductase (MTHFR) and EPAS1] are strongly associated with blood-related phenotypes, such as hemoglobin, homocysteine, and folate in Tibetans. The folate-increasing allele of rs1801133 at the MTHFR locus has an increased frequency in Tibetans more than expected under a drift model, which is probably a consequence of adaptation to high UV radiation. These findings provide important insights into understanding the genomic consequences of high-altitude adaptation in Tibetans.

Trio-based exome sequencing arrests de novo mutations in early-onset high myopia.

The etiology of the highly myopic condition has been unclear for decades. We investigated the genetic contributions to early-onset high myopia (EOHM), which is defined as having a refraction of less than or equal to -6 diopters before the age of 6, when children are less likely to be exposed to high educational pressures. Trios (two nonmyopic parents and one child) were examined to uncover pathogenic mutations using whole-exome sequencing. We identified parent-transmitted biallelic mutations or de novo mutations in as-yet-unknown or reported genes in 16 probands. Interestingly, an increased rate of de novo mutations was identified in the EOHM patients. Among the newly identified candidate genes, a BSG mutation was identified in one EOHM proband. Expanded screening of 1,040 patients found an additional four mutations in the same gene. Then, we generated Bsg mutant mice to further elucidate the functional impact of this gene and observed typical myopic phenotypes, including an elongated axial length. Using a trio-based exonic screening study in EOHM, we deciphered a prominent role for de novo mutations in EOHM patients without myopic parents. The discovery of a disease gene, BSG, provides insights into myopic development and its etiology, which expands our current understanding of high myopia and might be useful for future treatment and prevention.

Mutation spectrum and genotype-phenotype correlation of inherited retinal dystrophy in Taiwan.

BACKGROUND: Inherited retinal dystrophy (IRD) is a group of irreversible retinal degenerative disorders with significant genotypic and phenotypic heterogeneity, which cause difficulty in making a precise clinical diagnosis. Furthermore, the mutation spectrum of IRD in Taiwan remains unknown. Therefore, our study focused on investigating the spectrum of mutations among Taiwanese families with IRD using targeted exome sequencing (TES) technology. METHODS: We recruited a total of 60 unrelated Taiwanese families with IRD; most of them were retinitis pigmentosa. We employed TES to investigate 284 candidate genes. Bioinformatics analysis, Sanger sequencing-based co-segregation testing, and computational assessment were performed to validate each mutation and its pathogenicity. The genotype-phenotype correlation was analysed in all patients with mutations defined in the guidelines provided by the American College of Medical Genetics. RESULTS: We successfully identified genetic causes in 32 families (detection rate of 53.3%). Among them, 16 had a sporadic inheritance (16/36, 44.4%); eight had an autosomal recessive inheritance (8/14, 57.1%); four had an autosomal dominant inheritance (4/5, 80%); four had an X-linked inheritance (4/5, 80%). Among 38 pathological mutations in 19 known genes, 20 mutations are reported here for the first time. Novel mutation spectrum and genotype-phenotype correlations were revealed as well. CONCLUSION: Here we achieved a detection rate of 53.3% and elucidated the mutation spectrum in Taiwanese families with IRD for the first time. The results indicated that CYP4V2 and USH2A might be the most common pathogenic genes in IRD patients in Taiwan.

Functional characterization of CEP250 variant identified in nonsyndromic retinitis pigmentosa.

Retinitis pigmentosa (RP) is the most common manifestation of inherited retinal diseases with high degree of genetic, allelic, and phenotypic heterogeneity. CEP250 encodes the C-Nap1 protein and has been associated with various retinal phenotypes. Here, we report the identification of a mutation (c.562C>T, p.R188*) in the CEP250 in a consanguineous family with nonsyndromic RP. To gain insights into the molecular pathomechanism underlying CEP250 defects and the functional relevance of CEP250 variants in humans, we conducted a functional characterization of CEP250 variant using a novel Cep250 knockin mouse line. Remarkably, the disruption of Cep250 resulted in severe impairment of retinal function and significant retinal morphological alterations. The homozygous knockin mice showed significantly reduced retinal thickness and ERG responses. This study not only broadens the spectrum of phenotypes associated with CEP250 mutations, but also, for the first time, elucidates the function of CEP250 in photoreceptors using a newly established animal model.

REEP6 mediates trafficking of a subset of Clathrin-coated vesicles and is critical for rod photoreceptor function and survival.

In retinal photoreceptors, vectorial transport of cargo is critical for transduction of visual signals, and defects in intracellular trafficking can lead to photoreceptor degeneration and vision impairment. Molecular signatures associated with routing of transport vesicles in photoreceptors are poorly understood. We previously reported the identification of a novel rod photoreceptor specific isoform of Receptor Expression Enhancing Protein (REEP) 6, which belongs to a family of proteins involved in intracellular transport of receptors to the plasma membrane. Here we show that loss of REEP6 in mice (Reep6-/-) results in progressive retinal degeneration. Rod photoreceptor dysfunction is observed in Reep6-/- mice as early as one month of age and associated with aberrant accumulation of vacuole-like structures at the apical inner segment and reduction in selected rod phototransduction proteins. We demonstrate that REEP6 is detected in a subset of Clathrin-coated vesicles and interacts with the t-SNARE, Syntaxin3. In concordance with the rod degeneration phenotype in Reep6-/- mice, whole exome sequencing identified homozygous REEP6-E75K mutation in two retinitis pigmentosa families of different ethnicities. Our studies suggest a critical function of REEP6 in trafficking of cargo via a subset of Clathrin-coated vesicles to selected membrane sites in retinal rod photoreceptors.

Whole-exome sequencing identified ARL2 as a novel candidate gene for MRCS (microcornea, rod-cone dystrophy, cataract, and posterior staphyloma) syndrome.

Adenosine diphosphate (ADP)-ribosylation factor-like 2 (ARL2) protein participates in a broad range of cellular processes and acts as a mediator for mutant ARL2BP in cilium-associated retinitis pigmentosa and for mutant HRG4 in mitochondria-related photoreceptor degeneration. However, mutant ARL2 has not been linked to any human disease so far. Here, we identified a de novo variant in ARL2 (c.44G > T, p.R15L) in a Chinese pedigree with MRCS (microcornea, rod-cone dystrophy, cataract, and posterior staphyloma) syndrome through whole-exome sequencing and co-segregation analysis. Co-immunoprecipitation assay and immunoblotting confirmed that the mutant ARL2 protein showed a 62% lower binding affinity for HRG4 while a merely 18% lower binding affinity for ARL2BP. Immunofluorescence images of ARL2 and HRG4 co-localizing with cytochrome c in HeLa cells described their relationship with mitochondria. Further analyses of the mitochondrial respiratory chain and adenosine triphosphate production showed significant abnormalities under an ARL2-mutant condition. Finally, we generated transgenic mice to test the pathogenicity of this variant and observed retinal degeneration complicated with microcornea and cataract that were similar to those in our patients. In conclusion, we uncover ARL2 as a novel candidate gene for MRCS syndrome and suggest a mitochondria-related mechanism of the first ARL2 variant through site-directed mutagenesis studies.

Clinical Analysis of Sphenoid Sinus Mucocele With Initial Neurological Symptoms.

BACKGROUND AND OBJECTIVES: Neurological manifestations associated with sphenoid sinus mucocele (SSM) are easily misdiagnosed due to nonspecific symptoms. The objective is to analyze and report the clinical features of SSM presenting with neurological manifestations, to allow an earlier diagnosis and more timely intervention for this disease. METHODS: This was a retrospective cross-sectional study including 19 patients. The detailed clinical information of 19 patients with the initial symptom of neurological manifestations caused by SSM presenting at the Second Affiliated Hospital of Wenzhou Medical University between January 2000 and May 2018 were retrospectively analyzed. Collected data including symptoms, signs, neuroimaging, and pathologic diagnoses. RESULTS: There were eleven males and 8 females, and their ages ranged from 23 to 71 years. Headache was the most frequent symptom, in 12 of the 19 patients presenting as the initial symptom. The visual disturbance included visual loss (4/19), diplopia (3/19), and another patient had both visual loss and diplopia. Neurophysical examination found that 4 patients presented with oculomotor nerve palsy, 4 patients had optic nerve or abducens nerve palsy, and 1 patient had optic neuropathy, oculomotor nerve palsy and abducens nerve palsy simultaneously. All patients underwent endoscopic surgery and had postoperative clinical symptom improvement. CONCLUSIONS: Headache is the most common symptom of SSM and should be on the differential diagnosis of patients presenting with headache, even if in isolation. The results suggest that CT and MRI are the best tools in diagnosis of SSM and endoscopic sphenoidotomy is a safe and effective method in the treatment of SSM.

Estrogen is an important mediator of mast cell activation in ovarian endometriomas.

Endometriosis is an estrogen-dependent disease. Previous research has shown that abnormal enzymes associated with estrogen (E2) metabolism and an increased number of mast cells (MCs) in endometriomas are implicated in the pathogenesis of endometriosis. However, it remains unclear how MCs mediate the role of E2 in endometriosis. Accordingly, we investigated whether E2 was associated with the number of MCs, and the rate of degranulation, in local ovarian endometriomas, as well as the role of E2 on MCs during the pathogenesis of endometriosis. Using enzyme-linked immunosorbent assay and immunohistochemistry, we found that concentrations of E2, and the number and activity of MCs, were significantly higher in ovarian endometriomas than in controls, and that these parameters were correlated with the severity of endometriosis-associated dysmenorrhea. By measuring the release of hexosaminidase, we found that the rate of RBL2H3 cell degranulation increased after E2 treatment. Furthermore, activation of RBL2H3 cells by E2 was found to trigger the release of biologically active nerve growth factor, which promotes neurite outgrowth in PC12 cells and also sensitizes dorsal root ganglion cells via upregulation of Nav1.8 and transient receptor potential cation channel (subfamily V member 1) expression levels. When treated with E2, endometriotic cells could promote RBL2H3 cell recruitment by upregulating expression levels of stem cell factor, transforming growth factor-ß and monocyte chemoattractant protein-1; these observations were not evident with control endometrial cells. Thus, elevated E2 concentrations may be a key factor for degranulation and recruitment of MCs in ovarian endometriomas, which play a key role in endometriosis-associated dysmenorrhea.

Current Pharmacological Concepts in the Treatment of the Retinitis Pigmentosa.

Retinitis pigmentosa (RP) encompasses a heterogeneous group of inherited retinal disorders characterized by progressive photoreceptor and/or retinal pigment epithelial (RPE) degenerations with a prevalence approximately 1 in 4000 in the general population. Over 70 causative genes have been defined in RP families, and a number of animal models have been identified so far. However there have been no widely recognized treatments able to recover or reverse the degenerating retina, to prevent the disease deterioration, ultimately to restore the remaining vision. Therapeutics advancements have been achieved including gene therapy, pharmacotherapy, cell replacement, neurotrophic factors, and retinal prosthesis. In this review, we focus on the pharmaceutical drugs for RP with emphases on the context of drug discovery, development, and clinical translation.

CFHR2-rs2986127 as a genetic protective marker for acute anterior uveitis in Chinese patients.

BACKGROUND: Complement factor H (CFH) related proteins (CFHRs) play important roles in complement activation pathways, whereas previous studies have only shown that CFH can affect the development of uveitis. In the present study, we investigated the potential associations between one of single-nucleotide polymorphisms in the CFHR2 gene with acute anterior uveitis (AAU). METHODS: A total of 571 subjects, 283 patients diagnosed with AAU and 288 healthy adult controls, were recruited for this case-control study. CFHR2-rs2986127 was detected using Sequenom MassARRAY technology (Sequenom, San Diego, CA, USA). RESULTS: The stratified analyses for AAU patients with ankylosing spondylitis (AS) revealed a reduced frequency of the A allele in CFHR2-rs2986127 compared to controls (p = 0.033, odds ratio = 0.563, 95% confidence interval = 330-0.960). Further stratified analyses revealed a similar significantly reduced frequency in male AAU patients with AS compared to male controls (p = 0.036, odds ratio = 0.514, 95% confidence interval = 0.274-0.965) and in AAU patients without posterior segment involvement compared to controls (p = 0.048). CONCLUSIONS: The present study reveals an association between CFHR2-rs2986127 and AAU diagnosis, especially with respect to gender, AS status and other clinical signs, such as posterior segment involvement. Our results may further enrich the growing understanding of uveitis genetics, and raise the clinical diagnostic accuracy of this disease. Copyright © 2016 John Wiley & Sons, Ltd.

CFI-rs7356506 polymorphisms associated with Vogt-Koyanagi-Harada syndrome.

PURPOSE: Complement factor I (CFI) plays an important role in complement activation pathways and is known to affect the development of uveitis. The present study was performed to investigate the existence of an association between CFI genetic polymorphisms and Vogt-Koyanagi-Harada (VKH) syndrome. METHODS: A total of 100 patients diagnosed with VKH syndrome and 300 healthy controls were recruited for the study. Two milliliters of peripheral blood were collected in a sterile anticoagulative tube. CFI-rs7356506 polymorphisms were genotyped using Sequenom MassARRAY technology. Allele and genotype frequencies were compared between patients and controls using a χ(2) test. The analyses were stratified for recurrent status, complicated cataract status, and steroid-sensitive status. RESULTS: No significant association was found between CFI-rs7356506 polymorphisms and VKH syndrome. However, patients with recurrent VKH syndrome had lower frequencies of the G allele and GG homozygosity in CFI-rs7356506 when compared to the controls (p=0.016, odds ratio [OR]=0.429, 95% confidence interval [CI]=0.212-0.871; p=0.014, OR=0.364, 95% CI=0.158-0.837, respectively). Furthermore, there were significant decreases in the frequencies of the G allele and GG homozygosity in CFI-rs7356506 in patients with VKH syndrome with complicated cataract compared to the controls (p<0.001, OR=0.357, 95% CI=0.197-0.648; p<0.001, OR=0.273, 95% CI=0.135-0.551, respectively). Nevertheless, no significant association with patients with VKH syndrome in steroid-sensitive statuses was detected for CFI-rs7356506 polymorphisms. CONCLUSIONS: Our results indicate that CFI polymorphisms are not significantly associated with VKH syndrome; nevertheless, we identified a trend for the association of CFI-7356506 with VKH syndrome that depends on the recurrent status and the complicated cataract status but not on the steroid-sensitive status.

Identification of novel mutations by targeted exome sequencing and the genotype-phenotype assessment of patients with achromatopsia.

BACKGROUND: Achromatopsia (ACHM) is a severe congenital autosomal recessive retinal disorder caused by loss of cone photoreceptors. Here, we aimed to determine the underlying genetic lesions and phenotypic correlations in two Chinese families with ACHM. METHODS: Medical history and clinical evaluation were obtained from both families. Targeted exome sequencing (TES) was performed on 201 disease-causing genes of inherited retinal dystrophies to screen for ACHM causative mutations in the two probands. RESULTS: The compound heterozygous mutations in CNGA3 (c.1074G > A, p.W358X; c.1706G > A, p.R569H) were identified in the first proband, and a novel homozygous mutation (c.968C > A, p.A323D) was detected in the other pedigree. The proposed topological model of the CNGA3 polypeptide suggested that the missense mutations primarily affected the transmembrane helix 5 and the cGMP-binding domain, respectively. Crystal structure modeling of the cyclic nucleotide-gated cation channel α-3 (CNGA3) protein encoded by the CNGA3 gene revealed an abnormal combined structure generated by R569H. CONCLUSIONS: We firstly used the TES approach to identify genetic alterations in patients with ACHM. We uncovered three mutations in CNGA3, including one novel mutation. Our results not only expand the genotypic spectrum for CNGA3 mutations, but also demonstrate that the TES approach is a valuable tool for molecular diagnosis.

Identification of false-negative mutations missed by next-generation sequencing in retinitis pigmentosa patients: a complementary approach to clinical genetic diagnostic testing.

PURPOSE: Retinitis pigmentosa (RP) is a major cause of heritable human blindness with extreme genetic heterogeneity. A large number of causative genes have been defined by next-generation sequencing (NGS). However, due to technical limitations, determining the existence of uncovered or low-depth regions is a fundamental challenge in analyzing NGS data. Therefore, undetected mutations may exist in genomic regions less effectively covered by NGS. METHODS: To address this problem, we tested a complementary approach for identifying previously undetected mutations in NGS data sets. The strategy consisted of coverage-based analysis and additional target screening of low-depth regions. Fifty RP patients were analyzed, and none of the mutations found had previously been identified by NGS. RESULTS: Coverage-based analysis indicated that, because of a highly repetitive sequence, the RPGR open reading frame (ORF)15 was located in an uncovered or low-depth region. Through additional screening of ORF15, we identified pathogenic mutations in 14% (7/50) of patients, including four novel mutations first described herein. CONCLUSION: In brief, we support the need for a complementary approach to identify mutations undetected by NGS, underscoring the power and significance of combining coverage-based analysis with additional target screening of low-depth regions in improving diagnosis of genetic diseases. In addition to its usefulness in RP, this approach is likely applicable to other Mendelian diseases.

Genotype-phenotype correlation and mutation spectrum in a large cohort of patients with inherited retinal dystrophy revealed by next-generation sequencing.

PURPOSE: Inherited retinal dystrophy (IRD) is a leading cause of blindness worldwide. Because of extreme genetic heterogeneity, the etiology and genotypic spectrum of IRD have not been clearly defined, and there is limited information on genotype-phenotype correlations. The purpose of this study was to elucidate the mutational spectrum and genotype-phenotype correlations of IRD. METHODS: We developed a targeted panel of 164 known retinal disease genes, 88 candidate genes, and 32 retina-abundant microRNAs, used for exome sequencing. A total of 179 Chinese families with IRD were recruited. RESULTS: In 99 unrelated patients, a total of 124 mutations in known retinal disease genes were identified, including 79 novel mutations (detection rate, 55.3%). Moreover, novel genotype-phenotype correlations were discovered, and phenotypic trends noted. Three cases are reported, including the identification of AHI1 as a novel candidate gene for nonsyndromic retinitis pigmentosa. CONCLUSION: This study revealed novel genotype-phenotype correlations, including a novel candidate gene, and identified 124 genetic defects within a cohort with IRD . The identification of novel genotype-phenotype correlations and the spectrum of mutations greatly enhance the current knowledge of IRD phenotypic and genotypic heterogeneity, which will assist both clinical diagnoses and personalized treatments of IRD patients.