Circulating tumor DNA tracking in patients with pancreatic cancer using next-generation sequencing.

BACKGROUND: Pancreatic cancer remains one of the most devastating malignancies due to the absence of techniques for early diagnosis and the lack of target therapeutic options for advanced disease. Next Generation Sequencing (NGS) generates high throughput and valuable genetic information when evaluating circulating tumor DNA (ctDNA); however clinical utility of liquid biopsy in pancreatic cancer has not been demonstrated yet. The aim of this study was to evaluate whether results from a Next Generation Sequencing panel on plasma samples from pancreatic cancer patients could have a clinical significance. METHODS: From December 2016 to January 2020, plasma samples from 27 patients with pancreatic ductal adenocarcinoma at two different tertiary Spanish Hospitals underwent ctDNA testing using a commercial NGS panel of 65 genes. Clinical data were available for these patients. VarsSome Clinical software was used to analyse NGS data and establish pathogenicity. RESULTS: Evaluable NGS results were obtained in 18 out of the 27 plasma samples. Somatic pathogenic mutations were found mainly in KRAS, BRCA2, FLT3 and HNF1A, genes. Pathogenic mutations were detected in 50% of plasma samples from patient diagnosed at stages III-IV samples. FLT3 mutations were observed in 22.22% of samples which constitute a novel result in the field. CONCLUSIONS: Liquid biopsy using NGS is a valuable tool but still not sensitive or specific enough to provide clinical utility in pancreatic cancer patients.

Epidemiology of Melanoma in Spain: Estimation of Number of Patients With Stage III Disease Eligible for Adjuvant Therapies. / Epidemiología del melanoma en España: estimación de los pacientes con melanoma con estadio III candidatos al tratamiento adyuvante.

BACKGROUND AND OBJECTIVE: Accurate information on the incidence of melanoma by stage and a better understanding of transition between stages are important for determining the burden of disease and assessing the impact of new adjuvant therapies on recurrence and survival. The aim of this study was to estimate the incidence rates of the various stages of melanoma in Spain and to estimate the number of patients with stage III disease who are eligible for adjuvant systemic therapies. MATERIALS AND METHOD: We built an epidemiological model using prospectively collected data from patients diagnosed with de novo or recurrent melanoma between 2012 and 2016 in the melanoma units of 4 public hospitals. RESULTS: The estimated crude incidence rates for stage I and II melanoma were 7 and 2.9 cases per 100,000 person-years, respectively. The corresponding rates for stage III and IV melanoma were 1.9 and 1.3 cases per 100,000 person-years; 25.8% of patients with stage III melanoma were stage IIIA, 47% were stage IIIB, and 27.3% were stage IIIC. The respective estimated incidence rates for recurrent stage III and IV melanoma were 1.1 and 0.9 cases per 100,000 person-years. Overall, 54% of patients with recurrent stage III melanoma had progressed from stage I or II; the other cases corresponded to changes in substage. Of the patients with stage III melanoma, 85% of those with a de novo diagnosis and 80% of those who had relapsed had resectable disease, meaning they were eligible for adjuvant therapy; 47% of these patients had a BRAF mutation. CONCLUSIONS: The above estimates could have a major impact on health care resource planning. Assessing the number of patients with melanoma who are eligible for adjuvant therapies in melanoma could help decision-makers and clinicians anticipate future needs for the management of this disease.

Experiencia con el uso de olaparib en pacientes con cáncer de ovario.

INTRODUCTION: More than the twenty percent of ovarian cancers are hereditary, and most have BRCA mutations. The 30% of Mexican patients with the BRCA1 mutation have the BRCA1 gene exon 9-12del deletion founder mutation (BRCA1 ex9-12del). BRCA-mutated tumors are more sensitive to PARP inhibitors such as olaparib. OBJECTIVE: To show the clinical experience on the use of olaparib at Instituto Nacional de Cancerología in Mexico. METHOD: Ovarian cancer patients treated with olaparib from November 2016 to December 2018 were studied, and their characteristics, clinical response, progression-free survival (PFS) and toxicities were described. RESULTS: Nineteen patients were assessed, with BRCA1 mutation being found in 78.9%, out of which 21.1% were carriers of the ex9-12del founder mutation. The median of PFS was 12 months; for patients treated on second and third line it was > 15 months, and for those treated with a fourth and subsequent line it was 8.3 months. Patients with the founder mutation had better results. Toxicities were like those reported in previous studies. CONCLUSIONS: Olaparib offers greater PFS benefit as maintenance therapy after a first and second relapse. Patients with founder mutation have had sustained PFS.

INTRODUCCIÓN: Más del 20 % de los cánceres de ovario puede ser hereditario y la mayoría tiene mutaciones BRCA. El 33 % de las pacientes mexicanas con mutación BRCA1 tiene la mutación fundadora deleción del exón 9-12del del gen BRCA1 (BRCA1 ex9-12del). Los tumores BRCA mutados son más sensibles a inhibidores PARP como olaparib. OBJETIVO: Mostrar la experiencia clínica del uso de olaparib en el Instituto Nacional de Cancerología de México. MÉTODO: Se estudiaron las pacientes con cáncer de ovario tratadas con olaparib de noviembre de 2016 a diciembre de 2018 y se describieron sus características, respuesta clínica, supervivencia libre de progresión y toxicidades. RESULTADOS: Se evaluaron 19 pacientes, 78.9 % presentó mutación BRCA1, del cual 21.1 % era portador de la mutación fundadora ex9-12del. La mediana de supervivencia libre de progresión global fue de 12 meses, para las pacientes tratadas tratadas con olaparib de mantenimiento posterior a segunda y tercera línea fue de > 15 meses y para las de cuarta línea o más fue de 8.3 meses. Las pacientes con mutación fundadora presentaron mejores respuestas. Las toxicidades fueron similares a las de estudios con el uso de olaparib. CONCLUSIONES: Olaparib ofrece mayor beneficio en supervivencia libre de progresión como tratamiento de mantenimiento después de la primera y segunda recaída. Las pacientes con mutación fundadora han tenido respuesta sostenida.

Susceptibilidad genética frente al cáncer bucal por infección del virus del papiloma humano.

Environmental carcinogens and human papillomavirus (HPV) are the main responsible factors for oral cancer. Susceptibility factors in the human genome play a risk-modulating role; however not all individuals exposed to these carcinogens suffer from cancer. The purpose of the present review is to describe the main factors of genetic susceptibility to oral cancer due to HPV infection. A systematic search was carried out in three databases in English, with only 7 articles meeting the selection criteria. Genetic polymorphisms are shown in three categories, which are related to HPV and participate in oncogenesis. Three articles related to deregulation of cell cycle control mechanisms were identified, as well as one referring to mutations in the apoptosis pathway and three about polymorphisms in inflammatory and immune response genes. The association of polymorphisms for the development of oral cancer by HPV is evident, although it remains under study. Oral neoplasms' oncogenesis pattern is not always associated with HPV, but with other environmental or epigenetic factors.

Los carcinógenos ambientales y el virus del papiloma humano (VPH) son los principales responsables del cáncer bucal. Los factores de susceptibilidad en el genoma humano desempeñan un papel modulador del riesgo, sin embargo, no todos los individuos expuestos a los carcinógenos padecen cáncer. El objetivo de la presente revisión es describir los principales factores de susceptibilidad genética para cáncer bucal en individuos con infección por VPH. Se realizó una búsqueda sistemática en tres bases de datos en inglés; solo siete artículos cumplieron con los criterios de selección. Se registraron polimorfismos genéticos en tres categorías relacionados con el VPH y que participan en la oncogénesis. Se identificaron tres artículos relativos a la desregulación de los mecanismos de control del ciclo celular, uno relativo a mutaciones en la vía de la apoptosis y tres a polimorfismos en genes de respuesta inflamatoria e inmune. La asociación entre polimorfismos para el desarrollo de cáncer bucal y VPH es evidente, aunque continúa en estudio ya que no siempre el patrón de oncogénesis de las neoplasias bucales está relacionado con el VPH, sino con otros factores ambientales o epigenéticos.

Papel de la variabilidad genética en las enfermedades mendelianas y multifactoriales.

The first draft of the human genome sequencing published in 2001 reported a large number of single nucleotide polymorphisms (SNPs). Given that these polymorphisms could practically represent all the variability involved in the susceptibility, protection, severity, among other aspects, of various common diseases, as well as in their response to medications, it was thought that they might be "the biomarkers of choice" in personalized genomic medicine. With the new information obtained from the sequencing of a larger number of genomes, we have understood that SNPs are only an important part of the genetic markers involved in these traits. In addition to SNPs, other variants have been identified, such as insertions/deletions (INDELs) and copy number variants (CNVs), which - in addition to classic variable number tandem repeats (VNTRs) and short tandem repeats (STRs) - originate or contribute to the development of diseases. The use of these markers has served to identify regions of the genome involved in Mendelian diseases (one gene-one disease) or genes directly associated with multifactorial diseases. This review has the purpose to describe the role of STRs, VNTRs, SNPs, CNVs and INDELs in linkage and association studies and their role in Mendelian and multifactorial diseases.

El primer borrador de la secuencia del genoma humano, publicado en 2001, reportó gran cantidad de variantes de un solo nucleótido (SNP, single nucleotide polymorphisms). Debido a que estos polimorfismos podrían representar prácticamente toda la variabilidad involucrada en la susceptibilidad, protección, gravedad, etcétera, de diversas enfermedades comunes, así como en la respuesta de estas a los medicamentos, se pensó que podrían ser "los biomarcadores de elección" en la medicina genómica personalizada. Con la nueva información de la secuenciación de un mayor número de genomas hemos comprendido que los SNP son solo una parte importante de los marcadores genéticos involucrados en estos rasgos. Además de los SNP, se han identificado que otras variantes como las inserciones/deleciones (INDEL) y las variantes en el número de copia (CNV), las cuales ­ además de los clásicos repetidos en tándem de número variable (VNTR) y repetidos cortos en tándem (STR)­ originan o contribuyen al desarrollo de enfermedades. El uso de estos marcadores ha servido para identificar regiones del genoma involucradas en enfermedades mendelianas (un gen-una enfermedad) o genes directamente asociados con enfermedades multifactoriales. Esta revisión tiene como objetivo describir el papel de los STR, VNTR, SNP, CNV e INDEL en los estudios de ligamiento y asociación, y su papel en las enfermedades mendelianas y multifactoriales.

Splanchnic vein thrombosis as a first manifestation of Primary myelofibrosis / Trombosis venosa esplácnica como manifestación inicial de mielofibrosis primaria

Myeloproliferative neoplasms are chronic disorders of clonal hematopoietic stem cells, characterized by an overproduction of functional granulocytes, red blood cells and / or platelets, and one of the major complications is the occurrence of venous and arterial thrombotic problems caused by increased platelet aggregation and thrombin generation. In this study 11 cases of primary myelofibrosis (PM) were evaluated and 2 debuted with splanchnic venous thrombosis (SVT); so after seeing the results of this study and of world literature, it is suggested that in patients with SVT, diagnostic methods for PM like the JAK2V617F mutation should be included.

Las neoplasias mieloproliferativas (NMP) son alteraciones crónicas de las células madre hematopoyéticas clonales caracterizadas por una mayor producción de granulocitos, glóbulos rojos o plaquetas. Una de las principales complicaciones de las NMP es la aparición de problemas trombóticos venosos y arteriales causados por un aumento en la agregación plaquetaria y la generación de trombina. Se evaluaron 11 casos de mielofibrosis primaria (MP), de los cuales dos debutaron con trombosis venosa esplácnica (TVE). Tras observar los resultados de este estudio y de la literatura mundial, se sugiere que al evaluar pacientes con TVE se incluyan métodos diagnósticos para MP, como la mutación JAK2V617F.

Congenital Melanocytic Nevus Syndrome: A Case Series. / Síndrome del nevus melanocítico congénito. Serie de casos.

Congenital melanocytic nevus syndrome (CMNS) is the result of an abnormal proliferation of melanocytes in the skin and central nervous system caused by progenitor-cell mutations during embryonic development. Mutations in the NRAS gene have been detected in many of these cells. We present 5 cases of giant congenital melanocytic nevus, 3 of them associated with CMNS; NRAS gene mutation was studied in these 3 patients. Until a few years ago, surgery was the treatment of choice, but the results have proved unsatisfactory because aggressive interventions do not improve cosmetic appearance and only minimally reduce the risk of malignant change. In 2013, trametinib was approved for use in advanced melanoma associated with NRAS mutations. This drug, which acts on the intracellular RAS/RAF/MEK/pERK/MAPK cascade, could be useful in pediatric patients with CMNS. A better understanding of this disease will facilitate the development of new strategies.

[Treatment of non-cirrhotic, non-tumoural portal vein thrombosis]. / Actuación ante la trombosis portal no cirrótica no tumoral.

Thrombosis of the splenoportal axis not associated with liver cirrhosis or neoplasms is a rare disease whose prevalence ranges from 0.7 to 3.7 per 100,000 inhabitants. However, this entity is the second most common cause of portal hypertension. Prothrombotic factors are present as an underlying cause in up to 70% of patients and local factors in 10-50%. The coexistence of several etiological factors is frequent. Clinical presentation may be acute or chronic (portal cavernomatosis). The acute phase can present as abdominal pain, nausea, vomiting, fever, rectorrhagia, intestinal congestion, and ischemia. In this phase, early initiation of anticoagulation is essential to achieve portal vein recanalization and thus improve patient prognosis. In the chronic phase, symptoms are due to portal hypertension syndrome. In this phase, the aim of treatment is to treat or prevent the complications of portal hypertension. Anticoagulation is reserved to patients with a proven underlying thrombophilic factor.

Amino acid substitution in Cryptococcus neoformans lanosterol 14-α-demethylase involved in fluconazole resistance in clinical isolates.

The molecular basis of fluconazole resistance in Cryptococcus neoformans has been poorly studied. A common azole resistance mechanism in Candida species is the acquisition of point mutations in the ERG11 gene encoding the enzyme lanosterol 14-α-demethylase, target of the azole class of drugs. In C. neoformans only two mutations were described in this gene. In order to evaluate other mutations that could be implicated in fluconazole resistance in C. neoformans we studied the genomic sequence of the ERG11 gene in 11 clinical isolates with minimal inhibitory concentration (MIC) values to fluconazole of ≥16µg/ml. The sequencing revealed the G1855A mutation in 3 isolates, resulting in the enzyme amino acid substitution G484S. These strains were isolated from two fluconazole-treated patients. This mutation would not intervene in the susceptibility to itraconazole and voriconazole.

Characterization of phenotypic and genotypic drug resistance patterns of Mycobacterium tuberculosis isolates from a city in Mexico.

INTRODUCTION: The emergence of multidrug-resistant (MDR) Mycobacterium tuberculosis strains has become a worldwide health care problem, making treatment of tuberculosis difficult. The aim of this study was to determine phenotypic resistance and gene mutations associated with MDR of clinical isolates of Mycobacterium tuberculosis from Guadalajara, Mexico. METHODS: One hundred and five isolates were subjected to drug susceptibility testing to first line drugs using the proportion and Mycobacteria Growth Indicator Tube (MGIT) methods. Genes associated with isoniazid (inhA, katG, ahpC) and rifampicin (rpoB) resistance were analyzed by either pyrosequencing or PCR-RFLP. RESULTS: Resistance to any drug was detected in 48.6% of isolates, of which 40% were isoniazid-resistant, 20% were rifampicin-resistant and 19% were MDR. Drug-resistant isolates had the following frequency of mutations in rpoB (48%), katG (14%), inhA (26%), ahpC (26%). Susceptible isolates also had a mutation in ahpC (29%). CONCLUSIONS: This is the first analysis of mutations associated with MDR of M. tuberculosis in Guadalajara. Commonly reported mutations worldwide were found in rpoB, katG and inhA genes. Substitution C to T in position -15 of the ahpC gene may possibly be a polymorphism.

[New advances in hereditary colorectal cancer]. / Novedades en el cáncer colorrectal hereditario.

Colorectal cancer is the most frequent malignancy in both sexes in Spain. Between 20% and 25% of affected individuals have a family history of the disease, and 5% to 6% have a germ mutation, i.e. the disease develops in the context of a hereditary syndrome. The importance of identifying patients with hereditary syndromes predisposing them to colorectal cancer lies in the possibility of applying preventive measures, screening, and more appropriate management of both patients and their families. The present article outlines the most important studies presented at the congress of the American Gastroenterological Association.

Development of a simple microarray for genotyping HIV-1 drug resistance mutations in the reverse transcriptase gene in rural Tanzania.

OBJECTIVE: Aiming at a simple, inexpensive and robust tool for HIV-1 drug resistance genotyping during antiretroviral therapy (ART) we developed and validated a microarray-based detection of 25 drug resistance mutations most relevant for the Tanzanian ART regimen. METHODS: A reverse transcriptase gene fragment was reverse-transcribed and amplified by reverse transcription-polymerase chain reaction (RT-PCR). Primers for mini-sequencing were designed based on alignments of the most prevalent local HIV-1 variants. Tagged primers were extended by fluorochrome-labelled dideoxynuclotide triphosphate (ddNTPs) to indicate the single-nucleotide polymorphism (SNP) allele of the sample tested, followed by hybridisation on treated microarray slides. Images were analysed with a laser scanner and genotype calling was performed using in-house developed software. RESULTS: The microarray was validated with four cloned HIV-1 genome fragments from a Swiss HIV-1 cohort and 102 HIV-1 sequences amplified from the Tanzanian target population (field samples). Results were concordant with the Sanger sequencing SNP profile in 92.7% of 2550 SNP data points compared. Lack of signals in small number of SNPs was due to either failure in the extension reaction or hybridisation owing to mismatches between PCR product and extension primer. CONCLUSION: Our study demonstrates the feasibility of hybridisation-based genotyping of drug resistance mutations of HIV, even though our microarray, which was designed for population studies, achieved only correct assignment of 92% of all SNPs in the tested samples.

How do gene mutation diversity and disease severity scoring affect physical capacity and quality of life in children/adolescents with Familial Mediterranean Fever?

OBJECTIVES: The aim of this study is to examine how gene mutation diversity and disease severity affect physical capacity and quality of life in children/adolescents with Familial Mediterranean Fever (FMF). METHODS: Eighty children/adolescents (42 female, 38 male) diagnosed with FMF according to Tell-Hashomer diagnostic criteria were included in this study. Disease severity score (PRAS), running speed and agility and strength subtests of Bruininks-Oseretsky Test of Motor Proficiency Second Edition Short Form (BOT-2 SF), Physical Activity Questionnaire, Pediatric Quality of Life Inventory 3.0 Arthritis Module (PedsQL) was used for evaluation. Participants were divided into 2 groups as M694V and other mutations according to MEFV gene mutation and were divided into 3 groups as mild, moderate and severe according to PRAS. RESULTS: When the data were compared between groups; in terms of gene mutation, a significant difference was observed in treatment subtest of PedsQL-parent form in favor of the M694V gene mutation group (p<0.05). In terms of PRAS, significant difference was seen in the pain, treatment subtests and total score of the PedsQL-child form, and in the pain, treatment, worry subtests and total score of the PedsQL-parent form in favor of the mild group (p<0.05). CONCLUSIONS: MEFV gene mutations in children and adolescents with FMF did not differ on physical capacity and quality of life. PRAS was not effective on physical parameters, but quality of life decreased as the severity score increased. Encouraging children/adolescents with FMF to participate in physical activity and to support them psychosocially can be important to improve their quality of life.

Familial bilateral macronodular adrenal hyperplasia due to a novel ARMC 5 germline mutation: Clinical status and possible association with other neoplasms.

INTRODUCTION/OBJECTIVES: Mutations in the ARMC5 (armadillo repeat containing 5, OMIM 615549) gene, a putative tumor suppressor gene, have recently been identified as a common cause of sporadic and familial bilateral macronodular adrenal hyperplasia (BMAH). Familial BMAH is thought to be caused by two mutations, one germline and the other somatic, as suggested by the 2-hit theory. The objective is to describe a new mutation and develop its clinical characteristics and implications. METHODS, RESULTS AND CONCLUSIONS: We present an affected family with 11 members carrying a novel mutation of the ARMC5 gene (NM_001288767.1): c.2162T>C p. (Leu721Pro). Two of the carriers developed clinical Cushing's syndrome (CS), two mild autonomous cortisol secretion (MACS) and one presented with autonomous cortisol secretion (ACS). Four patients developed other tumors, three of whom died from this cause. It is not known whether these tumors could be related to the described mutation.

Langerhans cell histiocytosis mimicking acute dacryocystitis.

Langerhans cell histiocytosis (LCH) is a myeloid neoplasm characterized by clonal neoplastic proliferation of Langerhans-type dendritic cells associated with an inflammatory infiltrate predominantly composed of lymphocytes and eosinophils. In this article, we present an unusual case of LCH with significant swelling in the left lacrimal sac region in a 3-year-old child, clinically mimicking acute dacryocystitis. Microscopically, it showed intense inflammatory infiltrate and histiocytes with irregular nuclei. The tumor cells were positive for S-100 protein, CD1a, and CD207 (langerin). Molecular study was positive for the V600E/E2/D mutation (EXON 15). This case emphasizes the importance of careful clinical, radiographic, and microscopic evaluation, as some neoplasms may mimic common benign lesions.

Case report on activated PI3K-delta syndrome.

BACKGROUND: Activated phosphoinositide 3-kinase delta syndrome (APDS) [OMIM 615513] is an inborn error of immunity with autosomal dominant inheritance caused by a pathogenic variant in the PIK3CD gene. The prevalence ratio of APDS is < 1: 1,000,000 newborns. The main clinical features of APDS are sinopulmonary infections, benign lymphoproliferation, autoinflammatory disease, and a major risk of lymphoid neoplasms. CLINICAL CASE: A 17-year-old female with a history of pneumonia at 9 months of age subsequently developed recurrent respiratory tract infections, bronchiectasis, perforated otitis media, unilateral tonsillar lymphoid hyperplasia, pansinusitis, recurrent oral candidiasis, and chronic rhinitis. Laboratory studies reported persistent leukopenia and lymphopenia, low CD4 lymphocyte subpopulation, and persistently elevated immunoglobulin M immunoglobulin studies with values up to 692 mg/dL. An inborn error of immunity next-generation sequencing and multiplex ligation-dependent probe amplification analysis detected a heterozygous pathogenic variant in the PIK3CD gene, compatible with APDS. Treatment with monthly injectable gamma globulin and prophylactic antibiotics was started, allowing better control of the infectious processes. CONCLUSION: This is the second case of APDS reported in Mexico in the literature. It is important to be aware of this condition to make a timely diagnosis, which requires a high clinical suspicion and immunological and genetic studies to provide adequate treatment and prevent complications.

INTRODUCCIÓN: El síndrome de la Fosfoinositida 3-cinasa delta activado (Activated Phosphoinositide 3-kinase δ síndrome, APDS) [OMIM 615513] es un error innato de la inmunidad con patrón de herencia autosómica dominante causada por una variante patogénica heterocigota del gen PIK3CD. Su prevalencia es < 1: 1,000,000 nacidos vivos. Las principales manifestaciones clínicas son infecciones sinopulmonares, linfoproliferación benigna, autoinmunidad y aumento del riesgo de malignización linfoide. CASO CLÍNICO: Femenino de 17 años de vida con antecedentes de neumonía a los 9 meses de edad, posteriormente infecciones de vías respiratorias recurrentes, bronquiectasias, otitis media perforada, hiperplasia linfoide de amigdala unilateral, pansinusitis, candidiasis oral recurrente y rinitis crónica. Los estudios de laboratorio reportaron leuco linfopenia persistente, subpoblación linfocitaria con CD4 baja y estudios de inmunoglobulinas con IgM persistentemente elevada con valor de hasta 692 mg/dl. Se realizó estudio molecular de secuenciación de siguiente generación (NGS por sus siglas en inglés Next-Generation Sequencing) y amplificación de sondas dependientes de ligandos múltiples (MLPA por sus siglas en inglés Multiplex Ligation-dependent Probe Amplification) dirigido a errores innatos de la inmunidad que detectó una variante patogénica en estado heterocigoto en el gen PIK3CD, compatible con APDS. Se inició tratamiento con gammaglobulina intravenosa mensual y antibiótico profiláctico, permitiendo mejor control de los procesos infecciosos. CONCLUSIONES: Este es el segundo caso reportado en la literatura de APDS en México, por lo que es importante su conocimiento para poder realizar un diagnóstico oportuno, para el cual se requiere una alta sospecha clínica, además de estudios inmunológicos y genéticos, con la finalidad de otorgar el tratamiento adecuado y prevenir complicaciones.

Stargardt's pigmentosa: A novel combination of two inherited retinal dystrophies.

60-year-old woman referring visual disability. She presented bone spicule pigmentation and retinal atrophy in all peripheral retina, as well as macular retinal flecks. Multimodal imaging showed typical findings of both inherited retinal dystrophies (IRD). Electroretinogram confirmed rod dysfunction. Biallelic mutations were found in ABCA4 and CNGA1 genes. Although not common, different IRDs may be present in a same patient at the same time. This is the first reported case of the combination of RP with late-onset Stargardt's disease. We propose the name 'Stargardt's pigmentosa' for this novel clinical entity.

Novel quadruple mutations in dihydropteroate synthase genes of Plasmodium falciparum in West Bengal, India.

OBJECTIVE: To evaluate the anti-folate (sulphadoxine)-resistant pattern in Kolkata, one of the malaria endemic zones of Eastern India. METHODS: At first, 107 P. falciparum suspected cases were enrolled in this study. Ninety isolates (84.11%) of 107 suspected cases were analysed, as they had mono-infection with P. falciparum. In vitro susceptibility assays were performed in all 90 isolates. Parasitic DNA was isolated by phenol-chloroform extraction method and polymerase chain reaction was followed by restriction fragment length polymorphism analysis of different codons of the pfdhps gene (436, 437, 540, 581 and 613). RESULTS: Among 90 isolates from Kolkata, dhps mutant isolates at codons 436, 437, 540, 581 and 613 were found in 53.33%, 67.78%, 46.66%, 15.56% and 45.55%, respectively. In vitro sulphadoxine resistance was found in 49 isolates (54.44%). Interestingly we found 33 isolates (36.67%) with quadruple AGEAT mutant allele, of which 32 isolates (96.97%) were highly sulphadoxine resistant (P < 0.01) in vitro. CONCLUSION: Our present findings implicate that because of enormous drug (sulphfadoxine) pressure, novel AGEAT mutation was highly correlated (P < 0.01) with sulphadoxine resistance.

Analysis of SARS-CoV-2 mutations in the main viral protease (NSP5) and its implications on the vaccine designing strategies.

SARS-CoV-2 (Severe Acute Respiratory Syndrome), an etiolating agent of novel COVID-19 (coronavirus 2019) pandemic, rapidly spread worldwide, creating an unprecedented public health crisis globally. NSP5, the main viral protease, is a highly conserved protein, encoded by the genome of SARS-CoV-2 and plays an important role in the viral replication cycle. In the present study, we detected a total of 33 mutations from 675 sequences submitted from India in the month of March 2020 to April 2021. Out of 33 mutations, we selected 8 frequent mutations (K236R, N142L, K90R, A7V, L75F, C22N, H246Y and I43V) for further analysis. Subsequently, protein models were constructed, revealing significant alterations in the 3-D structure of NSP5 protein when compared to the wild type protein sequence which also altered the secondary structure of NSP5 protein. Further, we identified 9 B-cell, 10 T-cell and 6 MHC-I promising epitopes using predictive tools of immunoinformatics, out of these epitopes some were non-allergenic as well as highly immunogenic. Results of our study, however, revealed that 10 B-cell epitopes reside in the mutated region of NSP5. Additionally, hydrophobicity, physiochemical properties, toxicity and stability of NSP5 protein were estimated to demonstrate the specificity of the multiepitope candidates. Taken together, variations arising as a consequence of multiple mutations may cause alterations in the structure and function of NSP5 which generate crucial insights to better understand structural aspects of SARS-CoV-2. Our study also revealed, NSP5, a main protease, can be a potentially good target for the design and development of vaccine candidate against SARS-CoV-2.

El SARS-CoV-2 (Síndrome Respiratorio Agudo Severo), un agente etiológico de la nueva pandemia de COVID-19 (coronavirus 2019), se propagó rápidamente por todo el mundo y creó una crisis de salud pública sin precedentes a nivel mundial. El NSP5, la proteasa viral principal, es una proteína altamente conservada, codificada por el genoma del SARS-CoV-2 y juega un papel importante en el ciclo de replicación viral. En el presente estudio se detectaron un total de 33 mutaciones de 675 secuencias presentadas desde la India en el mes de marzo de 2020 a abril de 2021. De 33 mutaciones, se seleccionaron 8 mutaciones frecuentes (K236R, N142L, K90R, A7V, L75F, C22N, H246Y e I43V) para su posterior análisis. Posteriormente, se construyeron modelos proteicos que revelaron alteraciones significativas en la estructura 3D de las proteínas NSP5 en comparación con la secuencia de proteínas de tipo silvestre que también alteraron la estructura secundaria de la proteína NSP5. Además, se identificaron 9 epítopos prometedores de células B, 10 de células T y 6 de MHC-I, utilizando herramientas predictivas de inmunoinformática, algunos no alergénicos y altamente inmunogénicos. Los resultados de nuestro estudio, sin embargo, revelaron que 10 epítopos de células B residen en la región mutada de NSP5. Adicionalmente, se estimó la hidrofobicidad, propiedades fisicoquímicas, toxicidad y estabilidad de la proteína NSP5 para demostrar la especificidad de los candidatos multiepítopos. En conjunto, las variaciones que surgen como consecuencia de múltiples mutaciones pueden causar alteraciones en la estructura y función del NSP5 que generan conocimientos cruciales para entender mejor los aspectos estructurales del SARS-CoV-2. Nuestro estudio también reveló que el NSP5, una proteasa principal, puede ser un blanco potencialmente bueno para el diseño y desarrollo de la vacuna candidata contra el SARS-CoV-2.