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Upon completion of this activity, participants will be able to: In support of improving patient care, this activity has been planned and implemented by Medscape, LLC and Springer Nature. Medscape, LLC is jointly accredited by the Accreditation Council for Continuing Medical Education (ACCME), the Accreditation Council for Pharmacy Education (ACPE), and the American Nurses Credentialing Center (ANCC), to provide continuing education for the healthcare team. Medscape, LLC designates this Journal-based CME activity for a maximum of 1.0 AMA PRA Category 1 Credit(s)™. Physicians should claim only the credit commensurate with the extent of their participation in the activity. All other clinicians completing this activity will be issued a certificate of participation. To participate in this journal CME activity: (1) review the learning objectives and author disclosures; (2) study the education content; (3) take the post-test with a 75% minimum passing score and complete the evaluation at www.medscape.org/journal/eye ; (4) view/print certificate. 1.0 Release date: Expiration date: Post-test link: https://medscape.org/eye/posttest957229 Sobha Sivaprasad, MD, has disclosed the following relevant financial relationships: Served as an advisor or consultant for: Allergan, Inc.; Apellis; Bayer AG; Boehringer Ingelheim Pharmaceuticals, Inc.; Heidelberg Pharma GmbH; Novartis Pharmaceuticals Corporation; Oculis; Optos; Oxurion; Roche. Served as a speaker or a member of a speakers bureau for: Allergan, Inc.; Bayer AG; Novartis Pharmaceuticals Corporation; Optos. Received grants for clinical research from: Allergan, Inc.; Bayer AG; Boehringer Ingelheim Pharmaceuticals, Inc.; Novartis Pharmaceuticals Corporation; Optos. Meghana Tanwar, DNB, FRCS, has disclosed no relevant financial relationships. Sekaran Balaji, BSc, MSc, has disclosed no relevant financial relationships. Ayyasamy Vanniarajan, MSc, PhD, has disclosed no relevant financial relationships. Usha Kim, DO, DNB, has disclosed no relevant financial relationships. Gunja Chowdhury, DO, DNB, has disclosed no relevant financial relationships. Laurie Barclay, MD, has disclosed no relevant financial relationships. To determine the association between the parental age gap and the absolute parental age with the risk of retinoblastoma (RB) development in an offspring. RB individuals diagnosed between March 2013 and December 2019 in a single tertiary eye care centre were included. We recorded the demographic data, parental age and RB1 gene mutation status in the patient’s tumour, blood and the parental blood. We categorised RB1 mutation inheritance as sporadic RB with somatic mutations (only present in tumour), heritable RB with de novo (present in patient’s blood) and familial (present in patient and parents’ blood) germline mutations. The statistical significance was confirmed by Fisher’s exact/Chi-square test. Out of 259 RB patients, 247 were included in our study. Heritable RB with de novo germline mutations was significantly less common (p value: 0.0387; 95% CI: 0.2676–0.9329) and sporadic RB with somatic mutations was more common (p value: 0.0545; 95% CI: 1.025–3.39), if the parental age gap was

Idiopathic dilated cardiomyopathy (DCM) is a structural heart disease with strong genetic background. The aim of this study was to assess the role of mitochondrial DNA (mtDNA) variations and haplogroups in Indian DCM patients. Whole mtDNA analysis of 221 DCM patients revealed 48 novel, 42 disease-associated and 97 private variations. The frequency of reported variations associated with hearing impairment, DEAF, SNHL and LHON are significantly high in DCM patients than controls. Haplogroups H and HV were over represented in DCM than controls. Functional analysis of two private variations (m.8812A>G & m.10320G>A) showed decrease in mitochondrial functions, suggesting the role of mtDNA variations in DCM.

The tumor microenvironment (TME) constitutes multiple cell types including cancerous and non-cancerous cells. The intercellular communication between these cells through TME derived exosomes may either enhance or suppress the tumorigenic processes. The tumor-derived exosomes could convert an anti-tumor environment into a pro-tumor environment by inducing the differentiation of stromal cells into tumor-associated cells. The exosomes from tumor-associated stromal cells reciprocally trigger epithelial-to-mesenchymal transition (EMT) in tumor cells, which impose therapeutic resistance and metastasis. It is well known that these exosomes contain the signals of EMT, but how these signals execute chemoresistance and metastasis in tumors remains elusive. Understanding the significance and molecular signatures of exosomes transmitting EMT signals would aid in developing appropriate methods of inhibiting them. In this review, we focus on molecular signatures of exosomes that shuttle between cancer cells and their stromal populations in TME to explicate their impact on therapeutic resistance and metastasis through EMT. Especially Wnt signaling is found to be involved in multiple ways of exosomal transport and hence we decipher the biomolecules of Wnt signaling trafficked through exosomes and their potential in serving as therapeutic targets.

Purpose To estimate the prevalence of Leber hereditary optic neuropathy (LHON) along with genetic screening at a tertiary eye care center in southern India. Methods Patients with LHON were identified at the Neuro-Ophthalmology Clinic, Aravind Eye Hospital (AEH; Madurai, India) from 2015 to 2019. Clinical data were collected along with blood samples. Genetic testing was performed for the confirmation of LHON using a multiplex PCR restriction fragment length polymorphism (RFLP) approach to detect the primary mutations 3460A, 11778A, and 14484C in mitochondrial DNA (mtDNA). Results During the study period, 1,598,441 outpatients attended AEH of whom 40,527 were referred to the Neuro-Ophthalmology Clinic. Among them, 55 patients were diagnosed with LHON. The male to female ratio was 8.2:1.0, and the mean age at onset was 20.95 years (SD 8.940). The estimated prevalence was 1:737 or 13.57 per 10,000 (95% confidence intervals [CI] 10.23–17.66) at the Neuro-Ophthalmology Clinic. The frequency of primary mutations in the patients with LHON was determined as 43.6% (24/55), giving a prevalence of 1:1689 or 5.92 per 10,000 (95% CI 3.78–8.81). Conclusions The high prevalence of LHON observed at a single hospital highlights the impact of the disease in southern India. As the epidemiology of LHON remains unexplored in this region, these findings will pave the way to evaluate the national prevalence. Further, screening the whole mitochondrial genome may help to increase the detection of mutations to estimate the accurate prevalence of the disease.

Pseudogenes are duplicated or retrotransposed DNA sequences of native functional genes. Amplification of pseudogenes along with gene of interest often produces false positive results, which is an innate problem in Reverse Transcription-quantitative PCR (RT-qPCR). Selecting a reference gene without any interference from pseudogene amplification is therefore a challenge to overcome. Among the common reference genes used for normalization (ACTB, GAPDH, HPRT1, TUBB, RNA18SN1 and B2M), B2M was found to have no pseudogenes in silico, which has also been confirmed by PCR and RT-qPCR. We also assessed the effect of pseudogenes on the determination of the stability of reference genes through data mining. The phylogenetic analysis of pseudogenes and functional genes revealed high sequence similarity among mammals. In addition, we demonstrated the deduction of pseudogene amplification signal using ValidPrime Assay (VPA) under conditions where genomic DNA contamination could not be avoided. Hence, we recommend the use of pseudo-free reference gene with consistent expression in the samples of interest or use VPA normalization method, where genomic DNA or pseudogene amplification is inevitable.

Background: Retinoblastoma is a sight and life-threatening embryonal tumor in children. Though chemotherapy is the main mode of therapy, evolving resistance remains a major obstacle in treatment success. The presence of cancer stem cells (CSC) is frequently reported to be responsible for chemoresistance in multiple tumors. Objective: Our study aims to identify the molecular factors that facilitate the chemoresistance through cancer stem cells in retinoblastoma. Methods: We developed etoposide and carboplatin resistant retinoblastoma (Y79) cell lines by stepwise drug increment treatment, validated with MTT and TUNEL assays. Colony forming and invasive ability were studied by soft-agar colony forming and transwell assays, respectively. Similar analysis in non-responsive retinoblastoma tumors were carried out by histopathology. Finally, expression of CSC/neuronal markers and ABC transporters were examined by quantitative PCR and protein expression of neuronal stem cell markers was confirmed by Western blot. Results: Larger colony size of resistant cells in soft-agar assay provided evidence for increased selfrenewability. Histopathology in non-responsive tumors showed poorly differentiated cells predominantly. Besides, both resistant cell lines and non-responsive tumors showed increased invasion with higher expression of neuronal stem cell markers - SOX2, NANOG, OCT4 and ABC transporters - ABCB1 and ABCC3. Increased self-renewal ability and invasion along with overexpression of stemness markers in resistant cells and tumors provide evidence for stemness driving chemoresistance and invasion in retinoblastoma. Conclusion: We have demonstrated Neuronal stem cell/CSC markers that facilitate the maintenance of cancer stem cells. Developing therapies targeting these factors will help in overcoming resistance and improving retinoblastoma treatment.

Purpose: This study is aimed to investigate the presence of Human papillomavirus (HPV) DNA in tumors obtained from sporadic retinoblastoma patients. Methods: One hundred six tumor tissues obtained from sporadic RB patients were analyzed for HPV infection by use of both seminested PCR and real-time quantitative PCR. Results: Of 106 RB patients, 55 were male and 51 were female. The mean age at diagnosis was 26.77 ± 15.36 (mean ± Std. dev) months. Almost all patients presented with leukocoria. Molecular investigation by different methods revealed no HPV positivity in any tumor genome. Conclusion: Our study demonstrates no association between HPV and RB, postulating HPV may not be a major risk factor in the etiology of RB.

India has the highest number of retinoblastoma (RB) patients among the developing countries owing to its increasing population. Of the patients with RB, about 40% have the heritable form of the disease, making genetic analysis of the RB1 gene an integral part of disease management. However, given the large size of the RB1 gene with its widely dispersed exons and no reported hotspots, genetic testing can be cumbersome. To overcome this problem, we have developed a rapid screening strategy by prioritizing the order of exons to be analyzed, based on the frequency of nonsense mutations, deletions and duplications reported in the RB1-Leiden Open Variation Database and published literature on Indian patients. Using this strategy for genetic analysis, mutations were identified in 76% of patients in half the actual time and one third of the cost. This reduction in time and cost will allow for better risk prediction for siblings and offspring, thereby facilitating genetic counseling for families, especially in developing countries.

Purpose: Aldose reductase (ALR), the first and rate-limiting enzyme involved in polyol pathway plays a central role in diabetes and its related complications, including diabetic retinopathy (DR). Inhibition of ALR may also be an ideal target for reducing the deleterious effects of DR. Therefore, the purpose of the present study was to investigate the protective effect of epalrestat (EPL), ALR inhibitor on glucose-induced toxicity in ARPE-19 cells. Methods: ARPE-19 cells were challenged with normal glucose (NG, 5 mM) and high glucose (HG1, 25 mM and HG2, 50 mM) in the presence or absence of EPL. ALR and VEGF165 expression in retinal pigment epithelial (RPE) cells under experimental conditions were quantified by real-time polymerase chain reaction using SYBR Green chemistry. Vascular endothelial growth factor (VEGF) secretion in the cell supernatant was measured by Sandwich ELISA. Cytotoxicity of EPL was assessed by MTT assay. ALR inhibitory activity, apoptosis, and sorbitol accumulation were also ...

Chronic progressive external opthalmoplegia (CPEO) is the most common phenotypic syndrome of the mitochondrial myopathies. Muscle biopsy, which provides important morphological clues for the diagnosis of mitochondrial disorders, is normal in approximately 25% of patients with CPEO, thus necessitating molecular genetic analysis for more accurate diagnosis. We aimed to study the utility of various histochemical stains in the diagnosis of CPEO on muscle biopsy and to correlate these results with genetic studies. Between May 2005 and November 2007 all 45 patients diagnosed with CPEO were included in the study (23 males; mean age at presentation, 35 years). Thirty-nine patients had CPEO only and six had CPEO plus; two had a positive family history but the remaining 39 patients had sporadic CPEO. Muscle biopsy samples were stained with hematoxylin and eosin, modified Gomori's trichrome stain, succinic dehydrogenase (SDH), cytochrome C oxidase (COX) and combined COX-SDH. Ragged red fibers were seen in 27 biopsies; seven showed characteristics of neurogenic atrophy only, and 11 were normal. The abnormal fibers were best identified on COX-SDH stain. A complete mitochondrial genome was amplified in muscle and blood samples of all patients. Mutations were found in transfer RNA, ribosomal RNA, ND, CYTB, COX I, II and III genes. Mitochondrial gene mutations were found in ten of the 11 patients with a normal muscle biopsy. The genetic mutations were classified according to their significance. The observed muscle biopsy findings were correlated with genetic mutations noted. Histological studies should be combined with genetic studies for the definitive diagnosis of CPEO syndrome.

Background The spectrum of RB1gene mutations in Retinoblastoma (RB) patients and the necessity of multiple traditional methods for complete variant analysis make the molecular diagnosis a cumbersome, labor-intensive and time-consuming process. Here, we have used targeted next generation sequencing (NGS) approach with in-house analysis pipeline to explore its potential for the molecular diagnosis of RB. Methods Thirty-three patients with RB and their family members were selected randomly. DNA from patient blood and/or tumor was used for RB1 gene targeted sequencing. The raw reads were obtained from Illumina Miseq. An in-house bioinformatics pipeline was developed to detect both single nucleotide variants (SNVs) and small insertions/deletions (InDels) and to distinguish between somatic and germline mutations. In addition, ExomeCNV and Cn. MOPS were used to detect copy number variations (CNVs). The pathogenic variants were identified with stringent criteria, and were further confirmed by conventional methods and cosegregation in families. Results Using our approach, an array of pathogenic variants including SNVs, InDels and CNVs were detected in 85% of patients. Among the variants detected, 63% were germline and 37% were somatic. Interestingly, nine novel pathogenic variants (33%) were also detected in our study. Conclusions We demonstrated for the first time that targeted NGS is an efficient approach for the identification of wide spectrum of pathogenic variants in RB patients. This study is helpful for the molecular diagnosis of RB in a comprehensive and time-efficient manner.

Retinoblastoma (RB) is the most common primary intraocular malignancy affecting children under 5 years of age. This study aims to correlate the clinical parameters with RB1 mutation in the light of Knudson's two-hit hypothesis in Indian RB patients.We analyzed the clinical details of 73 RB patients visiting Aravind Eye Hospital, Madurai, India, between January and October 2012. Data on gender, presenting age and sign, laterality, number of tumors in each eye and family history were collected. A semi log plot was derived based on Knudson's two-hit hypothesis. Genetic analysis of RB1 was carried out to identify the two hits.The mean age at diagnosis for unilateral and bilateral cases was 24.0 ± 15.1 and 9.8 ± 11.5 months, respectively. Familial RB was seen in 13 (17.8%) patients of whom 11 were bilateral. Multiple tumors were observed more frequently in bilateral than in unilateral cases. All unilateral and bilateral patients followed the two-hit and one-hit curves, respectively, confirming Knudson's hypothesis in Indian patients. Genetic analysis identified two somatic mutations in tumor samples of sporadic unilateral cases. Among the two bilateral patients, one received the first hit from her father and the other patient developed a de novo germline mutation during early development.The two-hit hypothesis has been reestablished in Indian patients. Genetic analysis of tumor samples has also complemented the statistical analysis to reaffirm the two hits in tumor development.

We analyzed the complete mitochondrial genome of a 3-month-old female child with basal ganglionic lesions and other clinical features suggestive of Leigh syndrome, which is caused by variations in mitochondrial and nuclear genes. Our study revealed a novel, homoplasmic T11984C missense mutation in ND4 gene, which replaces a highly conserved amino acid tyrosine with histidine. Computational analysis showed that this mutation alters the secondary structure of ND4 subunit. As the mutation observed in this study was novel and homoplasmic, we speculate that there could be interplay of this mitochondrial mutation along with nuclear gene(s) in the pathogenesis.

We appreciate the effort shown by the authors and their comments on our article ‘‘Leber’s Hereditary Optic Neuropathy-Specific Mutation m.11778G>A Exists on Diverse Mitochondrial Haplogroups in India.’’ Leber’s hereditary optic neuropathy (LHON) is the most common, well-diagnosed, and maternally inherited mitochondrial disease. In this case, we would emphasize the statement that LHON is one of the most well characterized maternally inherited mitochondrial disease. We do agree with the statement that penetrance may depend on the age of individuals who carry the mutation. To date, our follow-up data do not reveal nonsymptomatic mutation carriers to have developed visual impairment and LHON. The data presented are to the best of our knowledge, till the time the manuscript was written. However, most of the families are in contact with the clinicians and have been informed about their genetic diagnosis. The families were followed up for the period of study (2005–2016), and patients were included if they developed visual disturbance. As discussed in the article, 13 out of 64 LHON families with m.11778G>A mutation were observed in heteroplasmic condition, and the remaining 51 were homoplasmic. In total (22 out of 145), 15% of manifesting mutation carriers was present with heteroplasmic form, while 31% of mutation carriers (124 out of 398) were present with homoplasmic condition. We do agree with the authors that knowledge of environmental factors (tobacco smoke) would greatly help in answering the penetrance of these LHON pedigrees. However, we realized during the study that quite a significant percentage of participants were not ready to share the details about their smoking and alcohol consumption history in an accurate way. At present, we lack proper details of the tobacco smoke and alcohol consumption for all the pedigrees and the amount of information, which we have, is not sufficient to make any specific conclusion about this issue. Keeping this in mind, we have decided to exclude this information from this study. During the initial analysis, 41 out of 64 index cases had positive family history of LHON. Seven affected individuals have mothers clinically manifesting LHON. During the course of this study, all the index cases were investigated for multiorgan involvement. We observed one patient from the index case had mild hepatosplenomegaly, while the other patients from index cases do not have any organ involvement. Hence, we would not be able to make conclusions about the multiorgan involvement and heteroplasmy level. None of the tRNA variants scored >11 on the Yarham score. One of the limitations was that we do not have all the information required for predicting the Yarham score for each patient due to absence of histology and transmitochondrial cybrid study for all the mutations. During initial clinical diagnosis of LHON-like symptoms for the patients, blood samples were collected for genetic diagnosis, which was confirmed by the presence of mutation. We, therefore, do not agree with collection of invasive samples like muscle biopsy in all the cases, but it was collected for a few cases where patients gave their consent. Hence, we were not able to perform all the analysis for predicting the Yarham score for additional variants observed together with m.11778G>A mutation. We also think it would be very difficult to segregate the effect of additional variant, since patients already have pathogenic mutation. We do agree with authors that pathogenicity of variants may be confirmed by using single fiber and cybrid analysis. However, it is not possible for us to make cybrids for all the variants; nevertheless, for the continuation of this project, we have a plan to select a few of the potential variants to study their role in different haplogroup backgrounds.

We measured the mitochondrial oxidative phosphorylation (mtOXPHOS) activities of all five complexes and determined the activity and gene expression in detail of the Complex III subunits in human breast cancer cell lines and primary tumors. Our analysis revealed dramatic differences in activity of complex III between normal and aggressive metastatic breast cancer cell lines. Determination of Complex III subunit gene expression identified over expression and co-regulation of UQCRFS1 (encoding RISP protein) and UQCRH (encoding Hinge protein) in 6 out of 9 human breast tumors. Analyses of UQCRFS1/RISP expression in additional matched normal and breast tumors demonstrated an over expression in 14 out of 40 (35%) breast tumors. UQCRFS1/RISP knockdown in breast tumor cell line led to decreased mitochondrial membrane potential as well as a decrease in matrigel invasion. Furthermore, reduced matrigel invasion was mediated by reduced ROS levels coinciding with decreased expression of NADPH oxidase 2, 3, 4 and 5 involved in ROS production. These studies provide direct evidence for contribution of impaired mtOXPHOS Complex III to breast tumorigenesis.

We performed an extensive study on mitochondrial dysfunction in chronic periodontitis (CP). Electron microscopic analysis of gingival cells revealed abnormal mitochondria in 60% of the patients. Mitochondrial membrane potential and oxygen consumption of gingival cells were reduced by 4 fold and 5.8 fold, respectively; whereas ROS production was increased by 18%. The genetic analysis by complete mitochondrial DNA sequencing revealed the identification of 14 novel mutations only in periodontal tissues but not in the blood, suggesting a role of oxidative stress on periodontal tissues. Thus, our functional and genetic analysis provided an evidence for the mitochondrial dysfunction in CP.

Several genetic factors have been found to be associated with recurrent pregnancy loss (RPL). However, not many attempts have been made to associate the mitochondrial DNA (mtDNA) variations with RPL. Therefore, we have analyzed the complete mtDNA of 100 women with RPL and 12 aborted fetal tissues. Our analysis revealed a total of 681 variations, most of which were in NADH Dehydrogenase (ND) genes that encode mitochondrial enzyme Complex I. Presence of T4216C variation (ND1 gene) in 9% of the RPL women and several pathogenic, and novel mutations suggest the role of mtDNA variations in RPL.

Mitochondrial encephalopathy lactic acidosis stroke like episodes (MELAS) is a progressive neurodegenerative disorder with varying age of onset. It is a clinically and genetically heterogeneous disease. Molecular etiology of MELAS is not known in several cases. We have identified a unique individual with late onset MELAS at the age of 55 years. We have analyzed the complete mitochondrial genome of the tissue and blood samples of the patient. One novel heteroplasmic mutation (C13565A) in NADH dehydrogenase 5 subunit (ND5) gene was found only in the tissue sample but not in the blood. This mutation is missense causing a change of amino acid serine to tyrosine at position 410. This mutation was found neither in controls nor in world populations. This study has also confirmed ND5 as a hotspot for the mitochondrial diseases. This will be of great help for the clinicians in the diagnosis of MELAS.

We have analyzed the mitochondrial DNA of 34 oligoasthenozoospermic men along with 150 normozoospermic fertile men from the Indian subcontinent. A novel missense mutation (C11994T) in the ND4 gene, which replaces threonine with isoleucine, was observed in all of the oligoasthenozoospermic men but not in any of the normozoospermic fertile men.

Purpose To investigate the clinical and mitochondrial DNA (mtDNA) haplogroup background of Indian Leber hereditary optic neuropathy (LHON) patients carrying the m.14484T>C mutation. Methods Detailed clinical investigation and complete mtDNA sequencing analysis was carried out for eight Indian LHON families with the m.14484T>C mutation. Haplogroup was constructed based on the evolutionarily important mtDNA variants. Results In the present study, we characterized eight unrelated probands selected from 187 LHON cases. The overall penetrance of the disease was estimated to be 19.75% (16/81) in eight pedigrees with the m.14484T>C mutation and showed substantially higher sex bias (male: female = 13:3). The mtDNA haplogrouping revealed that they belong to diverse haplogroups; i.e., F1c1, M31a, U2a, M*, I1, M6, M3a1, and R30a. Interestingly, we did not find an association of the m.14484T>C mutation with any specific haplogroup within the Indian population. We also did not find any secondary mutation(s) in these pedigrees, which might affect the clinical expression of LHON. Conclusions Contrary to earlier reports showing preferential association of the m.14484T>C mutation with western Eurasian haplogroup J and increased clinical penetrance when present in J1 subhaplogroup background, the present study shows that m.14484T>C arose independently in a different mtDNA haplogroup and ethnic background in India, which may influence the clinical expression of the disease.

We describe the clinical presentation, course and pathologic findings found in three adult patients with lipid storage myopathy. Excessive lipid storage was found in Type 1 fibers of muscle. Clinical improvement on oral levo-carnitine therapy suggests the possibility of carnitine deficiency as the most likely etiology in two of the patients and one had mitochondrial myopathy confirmed on genetic analysis.

Background Macrohaplogroups 'M' and 'N' have evolved almost in parallel from a founder haplogroup L3. Macrohaplogroup N in India has already been defined in previous studies and recently the macrohaplogroup M among the Indian populations has been characterized. In this study, we attempted to reconstruct and re-evaluate the phylogeny of Macrohaplogroup M, which harbors more than 60% of the Indian mtDNA lineage, and to shed light on the origin of its deep rooting haplogroups. Results Using 11 whole mtDNA and 2231 partial coding sequence of Indian M lineage selected from 8670 HVS1 sequences across India, we have reconstructed the tree including Andamanese-specific lineage M31 and calculated the time depth of all the nodes. We defined one novel haplogroup M41, and revised the classification of haplogroups M3, M18, and M31. Conclusion Our result indicates that the Indian mtDNA pool consists of several deep rooting lineages of macrohaplogroup 'M' suggesting in-situ origin of these haplogroups in South Asia, most likely in the India. These deep rooting lineages are not language specific and spread over all the language groups in India. Moreover, our reanalysis of the Andamanese-specific lineage M31 suggests population specific two clear-cut subclades (M31a1 and M31a2). Onge and Jarwa share M31a1 branch while M31a2 clade is present in only Great Andamanese individuals. Overall our study supported the one wave, rapid dispersal theory of modern humans along the Asian coast.