Literature search: Simple rules for confronting the unknown.

Literature search forms the foundation of most clinical decisions about patient management and is the starting point for all bedside/bench-side research. Despite being an essential tool in the armamentarium of all medical professionals and researchers, literature search remains a challenge, often resulting in frustration and waste of time (and resources). This article aims to provide a beginner's guide to information seekers for a step-wise approach to literature search on web-based databases.

Genome sequencing of SARS-CoV-2 omicron variants in Delhi reveals alterations in immunogenic regions in spike glycoprotein.

The SARS-CoV-2 omicron variants keep accumulating a large number of mutations in the spike (S) protein, which contributes to greater transmissibility and a rapid rise to dominance within populations. The identification of mutations and their affinity to the cellular angiotensin-converting enzyme-2 (ACE-2) receptor and immune evasion in the Delhi NCR region was under-acknowledged. The study identifies some mutations (Y505 reversion, G339H, and R346T/N) in genomes from Delhi, India, and their probable implications for altering the immune response and binding affinity for ACE-2. The spike mutations have influenced the neutralizing activity of antibodies against the omicron variant, which shows partial immune escape. However, researchers are currently exploring various mitigation strategies to tackle the potential decline in efficacy or effectiveness against existing and future variants of SARS-CoV-2. These strategies include modifying vaccines to target specific variants, such as the omicron variant, developing multivalent vaccine formulations, and exploring alternative delivery methods. To address this, it is also necessary to understand the impact of these mutations from a different perspective, especially in terms of alterations in antigenic determinants. In this study, we have done whole genome sequencing (WGS) of SARS-CoV-2 in COVID-19 samples from Delhi, NCR, and analyzed the spike's mutation with an emphasis on antigenic alterations. The impact of mutation in terms of epitope formation, loss/gain of efficiency, and interaction of epitopes with antibodies has been studied. Some of the mutations or variant genomes seem to be the progenitors of the upcoming variants in India. Our analyses suggested that weakening interactions with antibodies may lead to immune resistance in the circulating genomes.

Comorbidities in children with cerebral palsy: a single-centre cross-sectional hospital-based study from India.

OBJECTIVE: To describe the comorbidities in children with cerebral palsy (CP) and determine the characteristics associated with different impairments. DESIGN: Cross-sectional study. SETTING: Tertiary care referral centre in India. PATIENTS: Between April 2018 and May 2022, all children aged 2-18 years with a confirmed diagnosis of CP were enrolled by systematic random sampling. Data on antenatal, birth and postnatal risk factors, clinical evaluation and investigations (neuroimaging and genetic/metabolic workup) were recorded. MAIN OUTCOME MEASURES: Prevalence of the co-occurring impairments was determined using clinical evaluation or investigations as indicated. RESULTS: Of the 436 children screened, 384 participated (spastic CP=214 (55.7%) (spastic hemiplegic=52 (13.5%); spastic diplegia=70 (18.2%); spastic quadriplegia=92 (24%)), dyskinetic CP=58 (15.1%) and mixed CP=110 (28.6%)). A primary antenatal/perinatal/neonatal and postneonatal risk factor was identified in 32 (8.3%), 320 (83.3%) and 26 (6.8%) patients, respectively. Prevalent comorbidities (the test used) included visual impairment (clinical assessment and visual evoked potential)=357/383(93.2%), hearing impairment (brainstem-evoked response audiometry)=113 (30%), no understanding of any communication (MacArthur Communicative Development Inventory)=137 (36%), cognitive impairment (Vineland scale of social maturity)=341 (88.8%), severe gastrointestinal dysfunction (clinical evaluation/interview)=90 (23%), significant pain (non-communicating children's pain checklist)=230 (60%), epilepsy=245 (64%), drug-resistant epilepsy=163 (42.4%), sleep impairment (Children's Sleep Habits Questionnaire)=176/290(60.7%) and behavioural abnormalities (Childhood behaviour checklist)=165 (43%). Overall, hemiparetic and diplegic CP and Gross Motor Function Classification System ≤3 were predictive of lesser co-occurring impairment. CONCLUSION: CP children have a high burden of comorbidities, which increase with increasing functional impairment. This calls for urgent actions to prioritise opportunities to prevent risk factors associated with CP and organise existing resources to identify and manage co-occurring impairments. TRIAL REGISTRATION NUMBER: CTRI/2018/07/014819.

Two Novel Compound Heterozygous ADGRG1/GPR56 Mutations Associated with Diffuse Cerebral Polymicrogyria.

Background Polymicrogyria (PMG) has environmental or genetic etiologies. We report a 8-year-old boy with diffuse PMG and two novel adhesion G protein-coupled receptor G1 ( ADGRG1 ) / G protein-coupled receptor 56 ( GPR56 ) mutations. Case Report The proband has intellectual disability, spastic quadriparesis, and intractable epilepsy without antenatal or perinatal insults. Brain magnetic resonance imaging revealed PMG involving fronto-polar, parietal and occipital lobes with decreasing antero-posterior gradient, and a thinned-out brain stem. Targeted exome sequencing identified two novel compound heterozygote ADGRG1/GPR56 mutations (c.C209T and c.1010dupT), and each parent carries one of these mutations. Subsequent pregnancy was terminated because the fetus had the same mutations. Conclusion The detected mutations expanded the genetic etiology of PMG and helped the family to avoid another child with this devastating condition.

Somatic mutations involving TSC 1 and TSC2 genes in two children with focal cortical dysplasia.

BACKGROUND: The role of PI3K/AKT/mTOR pathway hyperactivation in localized brain overgrowth is evolving. We describe two patients with focal cortical dysplasia (FCD) who demonstrated somatic mutations in TSC1 and TSC2 genes in the dysplastic brain tissue but not peripheral blood. METHODS: Paired whole-exome sequencing was performed on genomic DNA extracted from blood and excised brain tissue in two children with FCD who underwent excision of dysplastic tissue. RESULTS: Patient 1, a 14-year boy, had drug-resistant focal epilepsy with onset at 20 months. His brain MRI showed abnormalities suggestive of FCD in the left superior and middle frontal lobes. Patient 2 presented at the age of 10 years with pharmaco-resistant focal epilepsy (onset at six years). His MRI suggested FCD in the left insular lobe. Both patients underwent surgical excision of FCD, and excised tissues were pathologically confirmed to have type IIb FCD. For patient 1, a missense mutation (c.64C > T; p.Arg22Trp) was detected in the TSC1 gene in DNA of dysplastic brain tissue but not peripheral blood lymphocytes. Similarly, for patient 2, a frameshift mutation (c.4258_4261delCAGT; p.Ser1420GlyfsTer55) in the TSC2 gene was identified in the brain tissue but not blood. Both gene variants are likely pathogenic and cause mTOR pathway activation. CONCLUSION: Our report of TSC1/TSC2 somatic mutations in patients with non-syndromic FCD suggests that localized hyperactivation of the mTOR pathway can cause focal malformations during cortical development and presents pharmacological targets for precision therapy in FCD management.

Clinical and molecular spectrum associated with Polymerase-γ related disorders.

BACKGROUND: POLG pathogenic variants are the commonest single-gene cause of inherited mitochondrial disease. However, the data on clinicogenetic associations in POLG-related disorders are sparse. This study maps the clinicogenetic spectrum of POLG-related disorders in the pediatric population. METHODS: Individuals were recruited across 6 centers in India. Children diagnosed between January 2015 and August 2020 with pathogenic or likely pathogenic POLG variants and age of onset <15 years were eligible. Phenotypically, patients were categorized into Alpers-Huttenlocher syndrome; myocerebrohepatopathy syndrome; myoclonic epilepsy, myopathy, and sensory ataxia; ataxia-neuropathy spectrum; Leigh disease; and autosomal dominant / recessive progressive external ophthalmoplegia. RESULTS: A total of 3729 genetic reports and 4256 hospital records were screened. Twenty-two patients with pathogenic variants were included. Phenotypically, patients were classifiable into Alpers-Huttenlocher syndrome (8/22; 36.4%), progressive external ophthalmoplegia (8/22; 36.4%), Leigh disease (2/22; 9.1%), ataxia-neuropathy spectrum (2/22; 9.1%), and unclassified (2/22; 9.1%). The prominent clinical manifestations included developmental delay (n = 14; 63.7%), neuroregression (n = 14; 63.7%), encephalopathy (n = 11; 50%), epilepsy (n = 11; 50%), ophthalmoplegia (n = 8; 36.4%), and liver dysfunction (n = 8; 36.4%). Forty-four pathogenic variants were identified at 13 loci, and these were clustered at exonuclease (18/44; 40.9%), linker (13/44; 29.5%), polymerase (10/44; 22.7%), and N-terminal domains (3/44; 6.8%). Genotype-phenotype analysis suggested that serious outcomes including neuroregression (odds ratio [OR] 11, 95% CI 2.5, 41), epilepsy (OR 9, 95% CI 2.4, 39), encephalopathy (OR 5.7, 95% CI 1.4, 19), and hepatic dysfunction (OR 4.6, 95% CI 21.3, 15) were associated with at least 1 variant involving linker or polymerase domain. CONCLUSIONS: We describe the clinical subgroups and their associations with different POLG domains. These can aid in the development of follow-up and management strategies of presymptomatic individuals.