A missense allele of PEX5 is responsible for the defective import of PTS2 cargo proteins into peroxisomes.

Peroxisomes, single-membrane intracellular organelles, play an important role in various metabolic pathways. The translocation of proteins from the cytosol to peroxisomes depends on peroxisome import receptor proteins and defects in peroxisome transport result in a wide spectrum of peroxisomal disorders. Here, we report a large consanguineous family with autosomal recessive congenital cataracts and developmental defects. Genome-wide linkage analysis localized the critical interval to chromosome 12p with a maximum two-point LOD score of 4.2 (θ = 0). Next-generation exome sequencing identified a novel homozygous missense variant (c.653 T > C; p.F218S) in peroxisomal biogenesis factor 5 (PEX5), a peroxisome import receptor protein. This missense mutation was confirmed by bidirectional Sanger sequencing. It segregated with the disease phenotype in the family and was absent in ethnically matched control chromosomes. The lens-specific knockout mice of Pex5 recapitulated the cataractous phenotype. In vitro import assays revealed a normal capacity of the mutant PEX5 to enter the peroxisomal Docking/Translocation Module (DTM) in the presence of peroxisome targeting signal 1 (PTS1) cargo protein, be monoubiquitinated and exported back into the cytosol. Importantly, the mutant PEX5 protein was unable to form a stable trimeric complex with peroxisomal biogenesis factor 7 (PEX7) and a peroxisome targeting signal 2 (PTS2) cargo protein and, therefore, failed to promote the import of PTS2 cargo proteins into peroxisomes. In conclusion, we report a novel missense mutation in PEX5 responsible for the defective import of PTS2 cargo proteins into peroxisomes resulting in congenital cataracts and developmental defects.

Novel mutations in LTBP2 identified in familial cases of primary congenital glaucoma.

Purpose: Primary congenital glaucoma (PCG) is a genetically heterogeneous disorder caused by developmental defects in the anterior chamber and trabecular meshwork. This disease is an important cause of childhood blindness. In this study, we aim to identify the genetic determinants of PCG in three consanguineous families of Pakistani descent. Methods: Affected members of all three families underwent detailed ophthalmological examination including slit-lamp biomicroscopy. Blood samples were collected from affected and healthy members of all three families, and genomic DNA was extracted. Linkage analysis was performed for the known or reported loci of PCG to localize the disease interval, and logarithm of odds (LOD) scores were calculated. All protein-coding exons of the candidate gene, latent transforming growth factor-beta binding protein 2 (LTBP2), were bidirectionally sequenced to identify the disease-causing mutation. Results: Short tandem repeat (STR) marker-based linkage analysis localized the critical interval to chromosome 14q with a maximum two-point LOD score of 2.86 (PKGL076), 2.8 (PKGL015), and 2.92 (PKGL042). Bidirectional Sanger sequencing of LTBP2 revealed three novel pathogenic variants, i.e., c.3028G>A (p.Asp1010Asn), c.3427delC (p.Gln1143Argfs*35), and c.5270G>A (p.Cys1757Tyr) in PKGL076, PKGL015, and PKGL042, respectively. All three mutations segregated with the disease phenotype in their respective families and were absent in 200 ethnically matched normal chromosomes. Conclusions: We identified three novel mutations, p.D1010N, p.Q1143Rfs*35, and p.C1757Y, in LTBP2 responsible for PCG.

Mutations in FYCO1 identified in families with congenital cataracts.

Purpose: This study was designed to identify the pathogenic variants in three consanguineous families with congenital cataracts segregating as a recessive trait. Methods: Consanguineous families with multiple individuals manifesting congenital cataracts were ascertained. All participating members underwent an ophthalmic examination. A small aliquot of the blood sample was collected from all participating individuals, and genomic DNAs were extracted. Homozygosity-based linkage analysis was performed using short tandem repeat (STR) markers. The haplotypes were constructed with alleles of the STR markers, and the two-point logarithm of odds (LOD) scores were calculated. The candidate gene was sequenced bidirectionally to identify the disease-causing mutations. Results: Linkage analysis localized the disease interval to chromosome 3p in three families. Subsequently, bidirectional Sanger sequencing identified two novel mutations-a single base deletion resulting in a frameshift (c.3196delC; p.His1066IlefsTer10) mutation and a single base substitution resulting in a nonsense (c.4270C>T; p.Arg1424Ter) mutation-and a known missense (c.4127T>C, p.Leu1376Pro) mutation in FYCO1. All three mutations showed complete segregation with the disease phenotype and were absent in 96 ethnically matched control individuals. Conclusions: We report two novel mutations and a previously reported mutation in FYCO1 in three large consanguineous families. Taken together, mutations in FYCO1 contribute nearly 15% to the total genetic load of autosomal recessive congenital cataracts in this cohort.

12 Month's Assessment Of Clinical Efficacy Of Resin Modified Glass Ionomer Cement And Flowable Composites In Restoration Of Non-Carious Cervical Lesions, A Randomized Clinical Trial.

Background: The objective of this study was to compare the clinical efficacy of Resin modified glass ionomer cement and Flowable composite in terms of retention, marginal adaptation and surface texture using United States Public Health Service criteria in non-carious cervical lesions measured over a period of one year. Methods: A Randomized Clinical Trial is conducted with Informed consent on 60 patients who are randomly allocated into 2 groups with at least 2 Non Carious Cervical Lesions in each. Group 1 is used for Flowable Composite while group 2 is used for resin modified glass ionomer cement. A recall is maintained to draw conclusions between two materials in terms of occurrence of marginal adaptation, retention and surface texture, to show which material is superior to other. Results: Out of 30 restorations in 12 months follow up, only 19 found to be present in flowable composite group while in resin modified glass ionomer cement group, 28 are retained. Regarding margin integrity, Group 1 showed 21 intact margins whereas 23 margins were intact in group 2, while 18 and 25 showed smooth surface in flowable composite and Resin modified glass ionomer cement group respectively, on exploration. Conclusion: It can be concluded from our study that Resin modified glass ionomer cement is superior to Flowable composite in terms of retention (p=0.005) and surface texture (p=0.045) in restoration of non carious cervical lesion.

Thalassaemia Patients with Polymorphism of COL1A1 Sp1 are at Greater Risk of Spine Degenerative Changes.

OBJECTIVE: To explore the association of the COL1A1 Sp1 polymorphism with decreased bone density and spinal changes in ß-thalassaemia patients. STUDY DESIGN: Cross-sectional, comparative study. Place and Duration of the Study: University of Health Sciences, Lahore, from May 2020 to June 2021. METHODOLOGY: A total of 110 participants (55patients and 55 controls) of either gender, with ages ranging from 18-40 years were enrolled in the study. Bone density parameters including T-score, Z-score, bone-transmission time (BTT), and amplitude-dependent speed of sound (ADSOS) were assessed by ultrasound bone profiler. Lumbar spine radiographs were collected from patients and assessed for spine changes. Genotype analysis was done by HRM-PCR. Data were analysed using SPSS version 23. RESULTS: All bone density parameters were significantly lower in ß-thalassaemai patients (p<0.001). Spine degenerative changes were more obvious in patients with age <25 years (p=0.04). Loss of lumbar lordosis was seen in 74.5% of the patients. The frequency of mutant allele (ss) was 7.3% while heterozygous (Ss) frequency was found to be 33.6%. The polymorphism showed significant association with T-scores (p=0.03) and ADSOS (p=0.02) in patients. Radiographic grades were higher in osteopenic and osteoporotic patients (p=0.04). CONCLUSION: The association of polymorphism with decreased bone density in ß-thalassaemia patients revealed the potential role of genetics in bone changes and related disorders. KEY WORDS: Bone Density, COL1A1 Polymorphism, Osteoporosis, Thalassaemia.

Effect Of Dental Proximal Restorations On Periodontal Health In Patients.

Background: The oral cavity is colonized by more than 700 species of bacteria and hundreds of those can be present within oral biofilms. Objective was to determine the frequency of periodontal attachment loss in patients with dental proximal restorations. Methods: This cross-sectional study included 100 patients with Class II (mesial /distal or mesio-occluso-distal composite and amalgam restorations. The minimum duration of pre-existing restoration for which periodontal attachment loss was assessed was more than 3 months. Patients wearing orthodontic appliances, pregnant women, patients having systemic health problems with well-established links to periodontal diseases such as diabetes mellitus and patients who had received periodontal treatment within the last 3 months were excluded. Periodontal Pocket depth and bleeding on probing was recorded using WHO periodontal probe. Pocket depth greater than 3 mm was considered pathologic. The data were analyzed using the SPSS, version 20. Descriptive statistics were computed. Chi square test was applied to compare the effects of duration of restoration and type of teeth on periodontal attachment loss. Results: Of total 100 participants 65 (65%) were males and 35 (35%) were females. The mean age was 30.74±9.21 years. In 14% cases having class II or Mesio occluso distal restorations normal pocket depth was recorded while 86% had pathologic pockets. Teeth where proximal restorations were present for more than one year were most commonly associated (29%) with pathologic pockets followed by proximal restorations which were present for three months (25%). As the duration of proximal restoration increased, the frequency of periodontal pathologic pockets increased (p<0.001). The prevalence of periodontal pocket was more in molars than premolars (p<0.001). Conclusion: Proximal restoration can be a significant risk factor for periodontal disease. Strict oral hygiene, proper design of restoration margin and supportive periodontal therapy is the utmost responsibility of the clinician.

A genomic deletion encompassing CRYBB2-CRYBB2P1 is responsible for autosomal recessive congenital cataracts.

Here we report a consanguineous Pakistani family with multiple affected individuals with autosomal recessive congenital cataract (arCC). Exclusion analysis established linkage to chromosome 22q, and Sanger sequencing coupled with PCR-based chromosome walking identified a large homozygous genomic deletion. Our data suggest that this deletion leads to CRYBB2-CRYBB2P1 fusion, consisting of exons 1-5 of CRYBB2 and exon 6 of CRYBB2P1, the latter of which harbors the c.463 C > T (p.Gln155*) mutation, and is responsible for arCC.

Next-generation whole exome sequencing to delineate the genetic basis of primary congenital glaucoma.

To delineate the genetic bases of primary congenital glaucoma (PCG), we ascertained a large cohort consisting of 48 consanguineous families. Of these, we previously reported 26 families with mutations in CYP1B1 and six families with LTBP2, whereas the genetic bases responsible for PCG in 16 families remained elusive. We employed next-generation whole exome sequencing to delineate the genetic basis of PCG in four of these 16 familial cases. Exclusion of linkage to reported PCG loci was established followed by next-generation whole exome sequencing, which was performed on 10 affected individuals manifesting cardinal systems of PCG belonging to four unresolved families along with four control samples consisting of genomic DNAs of individuals harboring mutations in CYP1B1 and LTBP2. The analyses of sequencing datasets failed to identify potential causal alleles in the 10 exomes whereas c.1169G > A (p. Arg390His) in CYP1B1 and c.3427delC (p.Gln1143Argfs*35) in LTBP2 were identified in the control samples. Taken together, next-generation whole exome sequencing failed to delineate the genetic basis of PCG in familial cases excluded from mutations in CYP1B1 and LTBP2. These data strengthen the notion that compound heterozygous coding variants or non-coding variants might contribute to PCG.

Correction: Missense Mutations in CRYAB Are Liable for Recessive Congenital Cataracts.

[This corrects the article DOI: 10.1371/journal.pone.0137973.].

Correction: Deletion at the GCNT2 Locus Causes Autosomal Recessive Congenital Cataracts.

[This corrects the article DOI: 10.1371/journal.pone.0167562.].

A spectrum of CYP1B1 mutations associated with primary congenital glaucoma in families of Pakistani descent.

Glaucoma is the second leading cause of blindness, affecting ~65 million people worldwide. We identified and ascertained a large cohort of inbred families with multiple individuals manifesting cardinal symptoms of primary congenital glaucoma (PCG) to investigate the etiology of the disease at a molecular level. Ophthalmic examinations, including slit-lamp microscopy and applanation tonometry, were performed to characterize the causal phenotype and confirm that affected individuals fulfilled the diagnostic criteria for PCG. Subsequently, exclusion analysis was completed with fluorescently labeled short tandem repeat markers, followed by Sanger sequencing to identify pathogenic variants. Exclusion analysis suggested linkage to the CYP1B1 locus, with positive two-point logarithm of odds scores in 23 families, while Sanger sequencing identified a total of 11 variants, including two novel mutations, in 23 families. All mutations segregated with the disease phenotype in their respective families. These included the following seven missense mutations: p.Y81N, p.E229K, p.R368H, p.R390H, p.W434R, p.R444Q and p.R469W, as well as one nonsense mutation, p.Q37*, and three frameshift mutations, p.W246Lfs81*, p.T404Sfs30* and p.P442Qfs15*. In conclusion, we identified a total of 11 mutations, reconfirming the genetic heterogeneity of CYP1B1 in the pathogenesis of PCG. To the best of our knowledge, this is the largest study investigating the contribution of CYP1B1 to the pathogenesis of PCG in the Pakistani population.

A Common Ancestral Mutation in CRYBB3 Identified in Multiple Consanguineous Families with Congenital Cataracts.

PURPOSE: This study was performed to investigate the genetic determinants of autosomal recessive congenital cataracts in large consanguineous families. METHODS: Affected individuals underwent a detailed ophthalmological examination and slit-lamp photographs of the cataractous lenses were obtained. An aliquot of blood was collected from all participating family members and genomic DNA was extracted from white blood cells. Initially, a genome-wide scan was performed with genomic DNAs of family PKCC025 followed by exclusion analysis of our familial cohort of congenital cataracts. Protein-coding exons of CRYBB1, CRYBB2, CRYBB3, and CRYBA4 were sequenced bidirectionally. A haplotype was constructed with SNPs flanking the causal mutation for affected individuals in all four families, while the probability that the four familial cases have a common founder was estimated using EM and CHM-based algorithms. The expression of Crybb3 in the developing murine lens was investigated using TaqMan assays. RESULTS: The clinical and ophthalmological examinations suggested that all affected individuals had nuclear cataracts. Genome-wide linkage analysis localized the causal phenotype in family PKCC025 to chromosome 22q with statistically significant two-point logarithm of odds (LOD) scores. Subsequently, we localized three additional families, PKCC063, PKCC131, and PKCC168 to chromosome 22q. Bidirectional Sanger sequencing identified a missense variation: c.493G>C (p.Gly165Arg) in CRYBB3 that segregated with the disease phenotype in all four familial cases. This variation was not found in ethnically matched control chromosomes, the NHLBI exome variant server, or the 1000 Genomes or dbSNP databases. Interestingly, all four families harbor a unique disease haplotype that strongly suggests a common founder of the causal mutation (p<1.64E-10). We observed expression of Crybb3 in the mouse lens as early as embryonic day 15 (E15), and expression remained relatively steady throughout development. CONCLUSION: Here, we report a common ancestral mutation in CRYBB3 associated with autosomal recessive congenital cataracts identified in four familial cases of Pakistani origin.

Deletion at the GCNT2 Locus Causes Autosomal Recessive Congenital Cataracts.

PURPOSE: The aim of this study is to identify the molecular basis of autosomal recessive congenital cataracts (arCC) in a large consanguineous pedigree. METHODS: All participating individuals underwent a detailed ophthalmic examination. Each patient's medical history, particularly of cataracts and other ocular abnormalities, was compiled from available medical records and interviews with family elders. Blood samples were donated by all participating family members and used to extract genomic DNA. Genetic analysis was performed to rule out linkage to known arCC loci and genes. Whole-exome sequencing libraries were prepared and paired-end sequenced. A large deletion was found that segregated with arCC in the family, and chromosome walking was conducted to estimate the proximal and distal boundaries of the deletion mutation. RESULTS: Exclusion and linkage analysis suggested linkage to a region of chromosome 6p24 harboring GCNT2 (glucosaminyl (N-acetyl) transferase 2) with a two-point logarithm of odds score of 5.78. PCR amplifications of the coding exons of GCNT2 failed in individuals with arCC, and whole-exome data analysis revealed a large deletion on chromosome 6p in the region harboring GCNT2. Chromosomal walking using multiple primer pairs delineated the extent of the deletion to approximately 190 kb. Interestingly, a failure to amplify a junctional fragment of the deletion break strongly suggests an insertion in addition to the large deletion. CONCLUSION: Here, we report a novel insertion/deletion mutation at the GCNT2 locus that is responsible for congenital cataracts in a large consanguineous family.

Mutation in LIM2 Is Responsible for Autosomal Recessive Congenital Cataracts.

PURPOSE: To identify the molecular basis of non-syndromic autosomal recessive congenital cataracts (arCC) in a consanguineous family. METHODS: All family members participating in the study received a comprehensive ophthalmic examination to determine their ocular phenotype and contributed a blood sample, from which genomic DNA was extracted. Available medical records and interviews with the family were used to compile the medical history of the family. The symptomatic history of the individuals exhibiting cataracts was confirmed by slit-lamp biomicroscopy. A genome-wide linkage analysis was performed to localize the disease interval. The candidate gene, LIM2 (lens intrinsic membrane protein 2), was sequenced bi-directionally to identify the disease-causing mutation. The physical changes caused by the mutation were analyzed in silico through homology modeling, mutation and bioinformatic algorithms, and evolutionary conservation databases. The physiological importance of LIM2 to ocular development was assessed in vivo by real-time expression analysis of Lim2 in a mouse model. RESULTS: Ophthalmic examination confirmed the diagnosis of nuclear cataracts in the affected members of the family; the inheritance pattern and cataract development in early infancy indicated arCC. Genome-wide linkage analysis localized the critical interval to chromosome 19q with a two-point logarithm of odds (LOD) score of 3.25. Bidirectional sequencing identified a novel missense mutation, c.233G>A (p.G78D) in LIM2. This mutation segregated with the disease phenotype and was absent in 192 ethnically matched control chromosomes. In silico analysis predicted lower hydropathicity and hydrophobicity but higher polarity of the mutant LIM2-encoded protein (MP19) compared to the wild-type. Moreover, these analyses predicted that the mutation would disrupt the secondary structure of a transmembrane domain of MP19. The expression of Lim2, which was detected in the mouse lens as early as embryonic day 15 (E15) increased after birth to a level that was sustained through the postnatal time points. CONCLUSION: A novel missense mutation in LIM2 is responsible for autosomal recessive congenital cataracts.

Missense Mutations in CRYAB Are Liable for Recessive Congenital Cataracts.

PURPOSE: This study was initiated to identify causal mutations responsible for autosomal recessive congenital cataracts in consanguineous familial cases. METHODS: Affected individuals underwent a detailed ophthalmological and clinical examination, and slit-lamp photographs were ascertained for affected individuals who have not yet been operated for the removal of the cataractous lens. Blood samples were obtained, and genomic DNA was extracted from white blood cells. A genome-wide scan was completed with short tandem repeat (STR) markers, and the logarithm of odds (LOD) scores were calculated. Protein coding exons of CRYAB were sequenced, bi-directionally. Evolutionary conservation was investigated by aligning CRYAB orthologues, and the expression of Cryab in embryonic and postnatal mice lens was investigated with TaqMan probe. RESULTS: The clinical and ophthalmological examinations suggested that all affected individuals had nuclear cataracts. Genome-wide linkage analysis suggested a potential region on chromosome 11q23 harboring CRYAB. DNA sequencing identified a missense variation: c.34C>T (p.R12C) in CRYAB that segregated with the disease phenotype in the family. Subsequent interrogation of our entire cohort of familial cases identified a second familial case localized to chromosome 11q23 harboring a c.31C>T (p.R11C) mutation. In silico analyses suggested that the mutations identified in familial cases, p.R11C and p.R12C will not be tolerated by the three-dimensional structure of CRYAB. Real-time PCR analysis identified the expression of Cryab in mouse lens as early as embryonic day 15 (E15) that increased significantly until postnatal day 6 (P6) with steady level of expression thereafter. CONCLUSION: Here, we report two novel missense mutations, p.R11C and p.R12C, in CRYAB associated with autosomal recessive congenital nuclear cataracts.