Molecular insights into TP53 mutation (p. Arg267Trp) and its connection to Choroid Plexus Carcinomas and Li-Fraumeni Syndrome.

BACKGROUND: Choroid plexus carcinomas (CPCs) are rare malignant tumors primarily affecting pediatric patients and often co-occur with Li-Fraumeni Syndrome (LFS), an inherited predisposition to early-onset malignancies in multiple organ systems. LFS is closely linked to TP53 mutations, with germline TP53 gene mutations present in approximately 75% of Li-Fraumeni syndrome families and 25% of Li-Fraumeni-like syndrome families. Individuals with TP53 mutations also have an elevated probability of carrying mutations in BRCA1 and BRCA2 genes. OBJECTIVE: To investigate the structural and functional implications of the TP53: 799C > T, p. (Arg267Trp) missense mutation, initially identified in a Saudi family, and understand its impact on TP53 functionality and related intermolecular interactions. METHODS: Computational analyses were conducted to examine the structural modifications resulting from the TP53: 799C > T, p. (Arg267Trp) mutation. These analyses focused on the mutation's impact on hydrogen bonding, ionic interactions, and the specific interaction with Cell Cycle and Apoptosis Regulator 2 (CCAR2), as annotated in UniProt. RESULTS: The study revealed that the native Arg267 residue is critical for a salt bridge interaction with glutamic acid at position 258. The mutation-induced charge alteration has the potential to disrupt this ionic bonding. Additionally, the mutation is located within an amino acid region crucial for interaction with CCAR2. The altered properties of the amino acid within this domain may affect its functionality and disrupt this interaction, thereby impacting the regulation of catalytic enzyme activity. CONCLUSIONS: Our findings highlight the intricate intermolecular interactions governing TP53 functionality. The TP53: 799C > T, p. (Arg267Trp) mutation causes structural modifications that potentially disrupt critical ionic bonds and protein interactions, offering valuable insights for the development of targeted mutants with distinct functional attributes. These insights could inform therapeutic strategies for conditions associated with TP53 mutations.

Exploring the untapped pharmacological potential of imidazopyridazines.

Imidazopyridazines are fused heterocycles, like purines, with a pyridazine ring replacing the pyrimidine ring in purines. Imidazopyridazines have been primarily studied for their kinase inhibition activity in the development of new anticancer and antimalarial agents. In addition to this, they have also been investigated for their anticonvulsant, antiallergic, antihistamine, antiviral, and antitubercular properties. Herein, we review the background and development of different imidazopyridazines as potential pharmacological agents. Moreover, the scope of this relatively less charted heterocyclic scaffold is also highlighted.

Novel LDLR Variant in Familial Hypercholesterolemia: NGS-Based Identification, In Silico Characterization, and Pharmacogenetic Insights.

BACKGROUND: Familial Hypercholesterolemia (FH) is a hereditary condition that causes a rise in blood cholesterol throughout a person's life. FH can result in myocardial infarction and even sudden death if not treated. FH is thought to be caused mainly by variants in the gene for the low-density lipoprotein receptor (LDLR). This study aimed to investigate the genetic variants in FH patients, verify their pathogenicity, and comprehend the relationships between genotype and phenotype. Also, review studies assessed the relationship between the LDLR null variants and the reaction to lipid-lowering therapy. METHODS: The study utilised high-throughput next-generation sequencing for genetic screening of FH-associated genes and capillary sequencing for cascade screening. Furthermore, bioinformatic analysis was employed to describe the pathogenic effects of the revealed novel variant on the structural features of the corresponding RNA molecule. RESULTS: We studied the clinical signs of hypercholesterolemia in a Saudi family with three generations of FH. We discovered a novel frameshift variant (c.666_670dup, p.(Asp224Alafs*43) in the LDLR and a known single nucleotide variant (c.9835A > G, p.(Ser3279Gly) in the APOB gene. It is thought that the LDLR variant causes a protein to be prematurely truncated, likely through nonsense-mediated protein decay. The LDLR variant is strongly predicted to be pathogenic in accordance with ACMG guidelines and co-segregated with the FH clinical characteristics of the family. This LDLR variant exhibited severe clinical FH phenotypes and was restricted to the LDLR protein's ligand-binding domain. According to computational functional characterization, this LDLR variant was predicted to change the free energy dynamics of the RNA molecule, thereby affecting its stability. This frameshift variant is thought to eliminate important functional domains in LDLR that are required for receptor recycling and LDL particle binding. We provide insight into how FH patients with a null variant in the LDLR gene respond to lipid-lowering therapy. CONCLUSIONS: The findings expand the range of FH variants and assist coronary artery disease preventive efforts by improving diagnosis, understanding the genotype-phenotype relationship, prognosis, and personalised therapy for patients with FH.

SARS-CoV-2 vaccine breakthrough infections (VBI) by Omicron variant (B.1.1.529) and consequences in structural and functional impact.

This study investigated the efficacy of existing vaccines against hospitalization and infection due to the Omicron variant of COVID-19, particularly for those who received two doses of Moderna or Pfizer vaccines and one dose of Johnson & Johnson vaccine or who were vaccinated more than five months before. A total of 36 variants in Omicron's spike protein, targeted by all three vaccinations, have made antibodies less effective at neutralizing the virus. The genotyping of the SARS-CoV-2 viral sequence revealed clinically significant variants such as E484K in three genetic mutations (T95I, D614G, and del142-144). A woman showed two of these mutations, indicating a potential risk of infection after successful immunization, as recently reported by Hacisuleyman (2021). We examine the effects of mutations on domains (NID, RBM, and SD2) found at the interfaces of the spike domains Omicron B.1.1529, Delta/B.1.1529, Alpha/B.1.1.7, VUM B.1.526, B.1.575.2, and B.1.1214 (formerly VOI Iota). We tested the affinity of Omicron for ACE2 and found that the wild- and mutant-spike proteins were using atomistic molecular dynamics simulations. According to the binding free energies calculated during mutagenesis, the ACE2 bound Omicron spikes more strongly than the wild strain SARS-CoV-2. T95I, D614G, and E484K are three substitutions that significantly contribute to RBD, corresponding to ACE2 binding energies and a doubling of the electrostatic potential of Omicron spike proteins. The Omicron appears to bind to ACE2 with greater affinity, increasing its infectivity and transmissibility. The spike virus was designed to strengthen antibody immune evasion through binding while boosting receptor binding by enhancing IgG and IgM antibodies that stimulate human ß-cell, as opposed to the wild strain, which has more vital stimulation of both antibodies.

Monoclonal antibody designed for SARS-nCoV-2 spike protein of receptor binding domain on antigenic targeted epitopes for inhibition to prevent viral entry.

SARS, or severe acute respiratory syndrome, is caused by a novel coronavirus (COVID-19). This situation has compelled many pharmaceutical R&D companies and public health research sectors to focus their efforts on developing effective therapeutics. SARS-nCoV-2 was chosen as a protein spike to targeted monoclonal antibodies and therapeutics for prevention and treatment. Deep mutational scanning created a monoclonal antibody to characterize the effects of mutations in a variable antibody fragment based on its expression levels, specificity, stability, and affinity for specific antigenic conserved epitopes to the Spike-S-Receptor Binding Domain (RBD). Improved contacts between Fv light and heavy chains and the targeted antigens of RBD could result in a highly potent neutralizing antibody (NAbs) response as well as cross-protection against other SARS-nCoV-2 strains. It undergoes multipoint core mutations that combine enhancing mutations, resulting in increased binding affinity and significantly increased stability between RBD and antibody. In addition, we improved. Structures of variable fragment (Fv) complexed with the RBD of Spike protein were subjected to our established in-silico antibody-engineering platform to obtain enhanced binding affinity to SARS-nCoV-2 and develop ability profiling. We found that the size and three-dimensional shape of epitopes significantly impacted the activity of antibodies produced against the RBD of Spike protein. Overall, because of the conformational changes between RBD and hACE2, it prevents viral entry. As a result of this in-silico study, the designed antibody can be used as a promising therapeutic strategy to treat COVID-19.

Identification of Novel and Known LDLR Variants Triggering Severe Familial Hypercholesterolemia in Saudi Families.

BACKGROUND: Familial hypercholesterolemia (FH) is a common illness mainly caused by variants occurring in the low-density lipoprotein receptor (LDLR) gene. FH is a leading cause of coronary artery disease. OBJECTIVE: This study aims to determine genetic defect(s) in homozygous and heterozygous FH index patients and their first-degree blood relatives and understand the genotype-phenotype correlation. METHODS: This study employed the genetic screening of FH-related genes by next-generation sequencing and cascade screening by capillary sequencing. RESULTS: We identified the presence of a novel frameshift variant [c.335_336insCGAG, p.(F114Rfs*17)] and three known missense variants [c.622G>A, p.(E208K)], [c.1474G>A, p.(D492N)], [c.1429G>A, p.(D477N)] in the LDLR gene of four unrelated Saudi families with FH. In proband 1, a nonsense variant c.1421C>G, p.(S474*) was also detected at exon 9 of the lipoprotein lipase gene. The segregation arrangement of the identified variants corresponded with the clinical characteristics. In this study, all the detected variants were confined in the ligand-binding domain and epidermal growth factor (EGF)-precursor homology domain of the LDLR protein, which portrayed severe clinical phenotypes of FH. Moreover, these LDLR variants were in a highly conserved residue of the proteins. CONCLUSION: In addition to the finding of the novel variant in the LDLR gene that extends the spectrum of variants causing FH, the results of this study also support the need for diagnostic screening and cascade genetic testing of this high-risk condition and to understand the genotype-phenotype correlation, which could lead to better prevention of coronary artery disease.

Targeted next-generation sequencing reveals novel and known variants of thrombophilia associated genes in Saudi patients with venous thromboembolism.

BACKGROUND: Thrombophilia is a substantial source of indisposition and mortality in several countries, including Arab populations. Deep venous thrombosis (DVT) with or without pulmonary embolism (PE) is the prevalent clinical manifestation of thrombophilia. While many genetic risk factors for DVT are known, almost all associated with hemostasis, many genetic factors remain unexplained. Nowadays, Next Generation Sequencing (NGS) offers a potential solution that allows several candidate genes to be analyzed simultaneously at a reasonable expense. METHODS: We performed variant screening in the thrombophilia associated genes in Factor V Leiden (FVL) mutation-negative patients using Ion Torrent Next-generation sequencing (NGS). Ion AmpliSeq panel for 18 genes was designed. Twenty-nine unrelated patients with idiopathic VTE were recruited for NGS. RESULTS: We were able to identify 19 variants (1 novel and 18 previously reported) in 10 out of 18 targeted genes. Pathogenic variants were identified in 22 patients demonstrating mutation detection rates of 76%. Previously reported variants in the F5, MTHFR, PROS1, PROC, F8, F9, SERPINA10, SERPIND1, and HRG genes were recognized in 21 patients. More than one variant in the targeted genes was detected in some of the patients with VTE. We identified SERPINA10 recurrent variant p.(R88*) in seven patients representing 32% of VTE cases. Additionally, we report one novel variant c.356G > T, p.(G119V) in the F7 gene, considered to be pathogenic in this study. CONCLUSIONS: Our studies finding illustrates the ability of targeted next-generation sequencing to uncover uncommon/unknown genetic variants that may predispose to thrombophilia. The finding of the novel variant in the F7 gene extends the spectrum of variants affecting thrombosis. While a comparatively small number of subjects have been included in our cohort, the findings summarize the possible genetic features of thrombophilia.

Peptides-based vaccine against SARS-nCoV-2 antigenic fragmented synthetic epitopes recognized by T cell and ß-cell initiation of specific antibodies to fight the infection.

The World Health Organization has declared the rapidly spreading coronavirus to be a global pandemic. The FDA is yet to approve a vaccine for human novel coronavirus. Here, we developed a peptide-based vaccine and used high-throughput screening by molecular dynamics simulation to identify T-cell- and ß-cell-recognized epitopes for producing specific antibodies against SARS-nCoV-2. We construct ~ 12 P' antigenic epitope peptides to develop a more effective vaccine and identify specific antibodies. These epitope peptides selectively presented the best antigen presentation scores for both human pMHC class I and II alleles to develop a strong binding affinity. All antigens identified of SARS-nCoV-2 different proteins by each attached specific ~ 1-7 L linker adaptor were used to construct a broad single peripheral peptide vaccine. It is expected to be highly antigenic with a minimum allergic effect. As a result of these exciting outcomes, expressing a vaccine using the intimated peptide was highly promising and positive to be highly proposed as epitope-based peptide vaccine of specific antibody against SARS-nCoV-2 by initiating T cells and ß-cells. An in vitro study for the proposed peptide-based vaccine is mostly recommended. Further clinical trials are required to check the efficacy of this vaccine.

Prevalence of the Factor V Leiden Mutation Arg534Gln in Western Region of Saudi Arabia: Functional Alteration and Association Study With Different Populations.

The rare Gln534 (Factor V Leiden; FVL) allele (1:169,519,049 T>C) is associated with an increased risk of venous thrombosis. The purpose of this study was to measure the prevalence of Factor V Leiden mutation in thrombophilia patients with deep vein thrombosis. Also, we investigated the functional and structural characteristics of this mutation p.(Arg534Gln) to be examined the cumulative impact on venous thrombosis risk as well correlated with different populations by Genome Wide Association Studies (GWAS). A total of 108 patients with idiopathic deep vein thrombosis were examined for Factor V Leiden gene mutation. Our preliminary data show that about 10% of patients were detected with the heterozygous and homozygous form of the Factor V Leiden mutation. An association analysis confirmed that the Factor V SNP variant (rs6025) was highly associated (P-value 4.91 x10-^ -39) with an increased risk of venous thrombosis. Also, we found that the recognized SNP was important among HapMap populations. Our results indicated that among the 3 populations (Asian, African, and American) studied, this association was highest in the African population based on the r(2) significant threshold (P-value 5e-190). In addition, this mutation was located at the domain F5/8 type A 2, which can disturb this domain and abolish its function. Because of aspartic acid nearby wild type position as form in the salt bridge due to this discharge will disturb the ionic interaction made by the wild type residue Arg534. This residue was not found to be in contact with other domains of which the function was known. However, contact with other molecules or domains (THPH2: MIM: 188055) were still possible and might be affected by this mutation that may cause thrombophilia due to activated protein C resistance.

New Imidazole-Based N-Phenylbenzamide Derivatives as Potential Anticancer Agents: Key Computational Insights.

An efficient atom-economical synthetic protocol to access new imidazole-based N-phenylbenzamide derivatives is described. A one-pot three-component reaction was utilized to provide a series of N-phenylbenzamide derivatives in a short reaction time (2-4 h) with an 80-85% yield. The cytotoxic evaluation revealed that derivatives 4e and 4f exhibited good activity, with IC50 values between 7.5 and 11.1 µM against the tested cancer cell lines. Computational studies revealed interesting insights: the docking of the active derivatives (4e and 4f) showed a higher affinity toward the target receptor protein than the control. Molecular dynamic simulations revealed that the active derivatives form stable complexes with the ABL1 kinase protein. Moreover, the ADME and drug-likeness of the derivatives reinforced the potential of the derivatives to be taken up for further development as anticancer agents.

Xanthomas Can Be Misdiagnosed and Mistreated in Homozygous Familial Hypercholesterolemia Patients: A Call for Increased Awareness Among Dermatologists and Health Care Practitioners.

Background: Familial hypercholesterolemia (FH) is an autosomal dominant inherited genetic disorder and results in the development of coronary artery disease (CAD). Clinical diagnosis of homozygous HH patients is usually straightforward because persistent hypercholesterolemia can produce xanthoma and corneal arcus. However, xanthoma may also be misdiagnosed as skin lesions and could therefore be mistreated. The aim of this case study report is to highlight the plight of patients with FH as means of raising awareness of the condition among dermatologists and health care practitioners, also to determine the genotype-phenotype correlation in severely affected homozygous FH proband patients. Methods: Genetic screening of FH associated genes was performed by Ion Torrent next-generation sequencing and cascade screening by capillary sequencing. Results: We present two clinical cases with prominent skin lesions seen in a dermatology clinic that were referred to plastic surgery for excision. Genetic testing was performed later, and confirmed common single nucleotide deletion variant (c.2027delG) in the LDLR alleles consequent to a frameshift mutation p.(G676Afs*33). In addition to the LDLR variant, two possibly damaging APOB variants p.(L3313I) and p.(L1212M) and three damaging variants p.(R19*), p.(G83Q) and p.(S474*) in APOC3, PON2 and LPL genes respectively were identified. The PON2 gene variant p.(G83Q) was found to be novel, while others have been previously reported. Both patients were refractory to pharmacological therapies and are currently on lipoprotein apheresis (LA). Conclusions: The present report indicates the need for increased awareness of FH, among the public and healthcare practitioners and supports the need for diagnostic screening and cascade genetic testing of this high-risk condition, which could ultimately lead to better prevention of CHD in this lethal condition.

Molecular Dynamics Simulation Reveals Exposed Residues in the Ligand-Binding Domain of the Low-Density Lipoprotein Receptor that Interacts with Vesicular Stomatitis Virus-G Envelope.

Familial hypercholesterolemia (FH) is an autosomal dominant disease most often caused by mutations in the low-density lipoprotein receptor (LDLR) gene, which consists of 18 exons spanning 45 kb and codes for a precursor protein of 860 amino acids. Mutations in the LDLR gene lead to a reduced hepatic clearance of LDL as well as a high risk of coronary artery disease (CAD) and sudden cardiac death (SCD). Recently, LDLR transgenes have generated interest as potential therapeutic agents. However, LDLR packaging using a lentiviral vector (LVV) system pseudotyped with a vesicular stomatitis virus (VSV)-G envelope is not efficient. In this study, we modified the LVV system to improve transduction efficiency and investigated the LDLR regions responsible for transduction inhibition. Transduction efficiency of 293T cells with a 5'-LDLReGFP-3' fusion construct was only 1.55% compared to 42.32% for the eGFP construct. Moreover, co-expression of LDLR affected eGFP packaging. To determine the specific region of the LDLR protein responsible for packaging inhibition, we designed constructs with mutations or sequential deletions at the 3' and 5' ends of LDLR cDNA. All constructs except one without the ligand-binding domain (LBD) (pWoLBD-eGFP) resulted in low transduction efficiency, despite successful packaging of viral RNA in the VSV envelope, as confirmed through RT-PCR. When we evaluated a direct interaction between LDLR and the VSV envelope glycoprotein using MD simulation and protein-protein interactions, we uncovered Val119, Thr120, Thr67, and Thr118 as exposed residues in the LDLR receptor that interact with the VSV protein. Together, our results suggest that the LBD of LDLR interacts with the VSV-G protein during viral packaging, which significantly reduces transduction efficiency.

Next generation DNA sequencing of atypical choroid plexus papilloma of brain: Identification of novel mutations in a female patient by Ion Proton.

Choroid plexus papilloma (CPP) is a rare benign tumor of the central nervous system that is usually confined to the cerebral ventricles. According to the World Health Organization, CPP corresponds to a grade I atypical CPP (a-CPP); however, it can become more aggressive and reach grade II, which can rarely undergo malignant transformation into a choroid plexus carcinoma (grade III). To the best of our knowledge, identification of these tumors mutations by next generation DNA sequencing (NGS) has not been yet reported. In the present study, NGS analysis of an a-CPP case was performed. Data were analyzed using Advaita Bioinformatics i-VariantGuide and Ion Reporter 5.6 programs. The results from NGS identified 12 novel missense mutations in the following genes: NOTCH1, ATM, STK36, MAGI1, DST, RECQL4, NUMA1, THBS1, MYH11, MALT1, SMARCA4 and CDH20. The PolyPhen score of six variants viz., DST, RECQL4, NUMA1, THBS1, MYHI1 and SMARCA4 were high, which suggested these variants represents pathogenic variants. Two novel insertions that caused frameshift were also found. Furthermore, two novel nonsense mutations and 14 novel intronic variants were identified in this tumor. The novel missense mutation detected in ATM gene was situated in c.5808A>T; p. (Leu1936Phe) in exon 39, and a known ATM mutation was in c.5948A>G; p. (Asn1983Ser). These novel mutations had not been reported in previous database. Subsequently, the quality statistics of these variants, including allele coverage, allele ratio, P-value, Phred quality score, sequencing coverage, PolyPhen score and alleles frequency was performed. For all variants, P-value was highly significant and the Phred quality score was high. In addition, the results from sequencing coverage demonstrated that 97.02% reads were on target and that 97.88% amplicons had at least 500 reads. These findings may serve at determining new strategies to distinguish the types of choroid plexus tumor, and at developing novel targeted therapies. Development of NGS technologies in the Kingdom of Saudi Arabia may be used in molecular pathology laboratories.

Modifying inter-cistronic sequence significantly enhances IRES dependent second gene expression in bicistronic vector: Construction of optimised cassette for gene therapy of familial hypercholesterolemia.

Internal ribosome entry site (IRES) sequences have become a valuable tool in the construction of gene transfer and therapeutic vectors for multi-cistronic gene expression from a single mRNA transcript. The optimal conditions for effective use of this sequence to construct a functional expression vector are not precisely defined but it is generally assumed that the internal ribosome entry site dependent expression of the second gene in such as cassette is less efficient than the cap-dependent expression of the first gene. Mainly tailoring inter-cistronic sequence significantly enhances IRES dependent second gene expression in bicistronic vector further in construction of optimised cassette for gene therapy of familial hypercholesterolemia. We tailored the size of the inter-cistronic spacer sequence at the 5' region of the internal ribosome entry site sequence using sequential deletions and demonstrated that the expression of the 3' gene can be significantly increased to similar levels as the cap-dependent expression of the 5' gene. Maximum expression efficiency of the downstream gene was obtained when the spacer is composed of 18-141 base pairs. In this case a single mRNA transcriptional unit containing both the first and the second Cistron was detected. Whilst constructs with spacer sequences of 216 bp or longer generate a single transcriptional unit containing only the first Cistron. This suggests that long spacers may affect transcription termination. When the spacer is 188 bp, both transcripts were produced simultaneously in most transfected cells, while a fraction of them expressed only the first but not the second gene. Expression analyses of vectors containing optimised cassettes clearly confirm that efficiency of gene transfer and biological activity of the expressed transgenic proteins in the transduced cells can be achieved. Furthermore, Computational analysis was carried out by molecular dynamics (MD) simulation to determine the most emerges as viable containing specific binding site and bridging of 5' and 3' ends involving direct RNA-RNA contacts and RNA-protein interactions. These results provide a mechanistic basis for translation stimulation and RNA resembling for the synergistic stimulation of cap-dependent translation.

Identification of six novel factor viii gene variants using next generation sequencing and molecular dynamics simulation.

Hemophilia A is an X-linked recessive hemorrhagic disorder caused by variants in the F8 gene. To identify known and novel causative variants in hemophilia A, we have carried out genetic analysis among Saudi patients. Twenty-one patients, who were negative for inv-1/inv-22, were selected for analysis by next generation sequencing, thereafter confirmed by Sanger sequencing. In addition, the functionality and structural changes in the variant proteins were assessed using Molecular dynamics (MD) simulation and compared with wild-type and native proteins. In the samples we analyzed, we found 10 variants in 12 individuals; among them, five were novel and five were previously reported. The novel variants were located at positions: c.6130_6131insC, c.5815G>C, c.5493C>G, c.3734_3740delinsATTTCT and c.3744A>T. With the exception of one variant which was silent, the MD simulation revealed that the observed variants were causing severe structural changes when compared to the native protein and resulted in a loss of the protein's function. The MD analysis is in line with clinical data of patients who had <1% Factor VIII levels (severe hemophilia) with episodic bleeding, and were on more than one treatment. Moreover, some patients presented with chronic joint disability. These results will enrich the spectrum of variants and enlarge the factor VIII protein's database in the Saudi Arabian population.

Comprehensive structure-function analysis of causative variants in retinal pigment epithelium specific 65 kDa protein associated Leber Congenital Amaurosis.

A recent study published to screen RPE65 in 187 families with Leber Congenital Amaurosis (LCA) by Zilin Zhong in 2019. There are seven novel variants were identified in RPE65, which was associated with LCA, but among only five were missense mutations [(c.124C > T, p.(Leu42Phe), c.149T > C, p. (Phe50Ser), c.340A > C, p.(Asn114His), c.425A > G, p.(Asp142Gly) and c.1399C > G, p.(Pro467Ala)] in the Chinese population and potentially facilitates its clinical implementation. Further in-continuation of this study to the target of five novel missense mutations were the analysis of both structural and functional impact by the molecular dynamics and simulation. The result of five missense mutations might in critical structural alterations of RPE65 protein, disrupt its membrane association or rescue the activity of enzyme due to thermodynamics stability, and for this reason impair its isomerohydrolase activity, resulting in retinal dystrophy. These observations suggest that the reduced protein stability and altered subcellular localization of RPE65 might signify a mechanism for these mutations to lead to vision loss in LCA patients.

Association of functional variants and protein-to-protein physical interactions of human MutY homolog linked with familial adenomatous polyposis and colorectal cancer syndrome.

The human gene MUTYH codes for a DNA glycosylase involved in the repair of oxidative DNA damage. Faulty MUTYH protein activity causes the accumulation of G→T transversions due to unrepaired 8-oxoG:A mismatches. MUTYH germ-line mutations in humans are linked with a recessive form of Familial Adenomatous Polyposis (FAP) and colorectal cancer predisposition. We studied the repair capacity of variants identified in MUTYH-associated polyposis (MAP) patients. MAP is inherited in an autosomal recessive type due to mutations in MUTYH (Y165C, G382D, P54S, A22V, Q63R, G45D, S136P and N43S), indicating that both copies of the gene become inactivated. However, the parents of an individual with an autosomal recessive condition may serve as carriers, each harboring one copy of the mutated gene without showing signs or symptoms of MAP. Six protein partners have been associated with MUTYH, four via direct physical interactions, namely, hMSH6, hPCNA, hRPA1, and hAPEX1. We examined, for the first time, specific interactions of these protein partners with MAP-associated MUTYH mutants using molecular dynamics simulations. The approach provided tools for exploration of the conformational energy landscape accessible to protein partners. The investigation also determined the impact before and after energy minimization of protein-protein interactions and binding affinities of MUTYH wild type and mutant forms, as well as the interactions with other proteins. Taken together, this study provided new insights into the role of MUTYH and its interacting proteins in MAP.

Mutation profiling of anaplastic ependymoma grade III by Ion Proton next generation DNA sequencing.

Background: Ependymomas are glial tumors derived from differentiated ependymal cells. In contrast to other types of brain tumors, histological grading is not a good prognostic marker for these tumors. In order to determine genomic changes in an anaplastic ependymoma, we analyzed its mutation patterns by next generation sequencing (NGS). Methods:  Tumor DNA was sequenced using an Ion PI v3 chip on Ion Proton instrument and the data were analyzed by Ion Reporter 5.6. Results: NGS analysis identified 19 variants, of which four were previously reported missense variants; c.395G>A in IDH1, c.1173A>G in PIK3CA, c.1416A>T in KDR and c.215C>G in TP53. The frequencies of the three missense mutations ( PIK3CA c.1173A>G, KDR c.1416A>T, TP53, c.215C>G) were high, suggesting that these are germline variants, whereas the IDH1 variant frequency was low (4.81%). However, based on its FATHMM score of 0.94, only the IDH1 variant is pathogenic; other variants TP53, PIK3CA and KDR had FATHMM scores of 0.22, 0.56 and 0.07, respectively. Eight synonymous mutations were found in FGFR3, PDGFRA, EGFR, RET, HRAS, FLT3, APC and SMAD4 genes. The mutation in FLT3 p.(Val592Val) was the only novel variant found. Additionally, two known intronic variants in KDR were found and intronic variants were also found in ERBB4 and PIK3CA. A known splice site mutation at an acceptor site in FLT3, a 3'-UTR variant in the CSF1R gene and a 5'_UTR variant in the SMARCB1 gene were also identified. The p-values were below 0.00001 for all variants and the average coverage for all variants was around 2000x. Conclusions: In this grade III ependymoma, one novel synonymous mutation and one deleterious missense mutation is reported. Many of the variants reported here have not been detected in ependymal tumors by NGS analysis previously and we therefore report these variants in brain tissue for the first time.

Structural and Functional Analysis of human lung cancer risk associated hOGG1 variant Ser326Cys in DNA repair gene by molecular dynamics simulation.

Oxidative damaged DNA base lesions are repaired through human 8-oxoguanine DNA glycosylase gene (hOGG1) mediated pathways. A recent report based on the meta-analysis has suggested that the DNA Repair Gene hOGG1 variant Ser326Cys [3p26.2; allele S/C in nucleotide position αHelix2 Ser⇒Cys326] was associated with Lung Cancer risk in Caucasian population will alter the level Zhong et al., 2012. To the best of our knowledge, there has not been any such comprehensive in-silico investigation that validates the functional and structural impact of non-synonymous Lung Cancer Risk Associated Protein Domain (LCRAPD) mutation Ser326Cys (rs1052133) by molecular dynamics (MD) simulation approach following prediction of hOGG1 protein before and after the mutation. Further to the native and mutant protein structures, the amino acid residue and its secondary structure were observed through a solvent accessibility model for protein stability confirmation at the point of mutation. Taken together, this study suggests that the protein functional and structural studies could be a reasonable approach for investigating the impact of nsSNPs in future studies. In addition, 4295 patients samples incorporate with the analysis that genomic data types from cBioPortal. In the result, 4295 cases (91.5%) had alterations in all genes but the frequency of alterations in our targeted hOGG1 gene was shown with and without case alteration in the ratio (Logrank Test P-Value: 0.670) Kaplan-Meier by the number of patients at risk of the survival function.

Novel combined variants of LDLR and LDLRAP1 genes causing severe familial hypercholesterolemia.

BACKGROUND AND AIMS: Familial hypercholesterolemia (FH) is a predominantly autosomal dominant hereditary disorder with significant potential for expansion of coronary artery disease. METHODS: To identify candidate variant/s in FH phenotype implicated genes, next-generation sequencing was performed using a targeted customized gene panel. RESULTS: We recognized a 45-year-old Saudi female FH patient with double variants in the LDLR [c.1255 T > G, p.(Y419D)] and LDLRAP1 genes [c.604_605delTCinsA, p.(S202Tfs*2)]. The proband was found to be homozygous for the LDLR variant and heterozygous for the LDLRAP1 variant. Three of the proband's children were found to be double heterozygous for the LDLR/LDLRAP1 gene variant. While her other three children were heterozygous for the same single LDLR variant. Both variants were not previously reported. The variants segregation pattern correlated with the clinical picture and with the patient's lipid profile. FH severity was greater in the proband while her children did not show any clinical manifestations. The missense variant p.(Y419D) was found to be deleterious and clinically significant based on prediction identified by PolyPhen-2 and Proven. Molecular dynamics simulation was used to further analyze the effect of the variant p.(Y419D) on the structure and function of the LDLR protein. The secondary structure was investigated, as well as the solvent accessibility and stabilizing residues. The frameshift variant of the LDLRAP1 gene results in a truncated peptide that could affect the cellular internalization of LDLR/LDL complex. CONCLUSIONS: The finding of the combined variants in LDLR/LDLRAP1 genes triggering a severe FH phenotype is essential to elaborate the spectrum of variants causing FH and to understand the genotype-phenotype correlation.