Association Between Neonatal Thyroid Stimulating Hormone Status and Maternal Urinary Iodine Status

BACKGROUND

Maternal urinary iodine concentration (MUIC) and percentage of neonates with Thyroid stimulating hormone (TSH) >5 mIU/L are amongst the parameters suggested for assessing adequate iodine status.

OBJECTIVE

To assess the correlation between MUIC and neonatal TSH levels.

STUDY DESIGN

Cross-sectional.

SETTINGS

Tertiary care center in Delhi, India, between November 2015 to November 2016.

PARTICIPANTS

Postnatal mother-neonate dyads.

METHODS

TSH levels assessed among neonatal samples were stratified as below and above 5 mIU/L. MUIC was measured in 544 mothers, 400 mother-neonate dyads with neonatal TSH levels >5 mIU/L (cases) and 144 mother-neonate newborn mother dyads with neonatal TSH <5 mIU/L (controls).

RESULTS

Results: The percentage of mothers with iodine insufficiency (9.8% vs 5.6%) as well as iodine excess (54.3% vs 41.7%) were significant higher in cases than controls. Mean TSH was also higher (P=0.0002) in both the iodine deficient and iodine excess group. There was no correlation between neonatal TSH values and MUIC.

CONCLUSION

Lack of correlation between neonatal TSH and MUIC is due to iodine excess together with iodine deficiency.

Pharmacophore modeling and virtual screening in search of novel Bruton's tyrosine kinase inhibitors

Bruton's tyrosine kinase (BTK) is a known drug target for B cell malignancies and autoimmune diseases like rheumatoid arthritis. Consequently, efforts to develop BTK inhibitors have gained momentum in the last decade, resulting in a number of potential inhibitory molecules. However, to date, there are only two FDA approved drugs for B cell malignancies (Ibrutinib and Acalabrutinib), thus continued efforts are warranted. A large number of molecular scaffolds with potential BTK inhibitory activity are already available from these studies, and therefore we employed a ligand-based approach towards computer-aided drug design to develop a pharmacophore model for BTK inhibitors. Using over 400 molecules with known half maximal inhibitory concentrations (IC₅₀) for BTK, a four-point pharmacophore hypothesis was derived, with two aromatic rings (R), one hydrogen bond acceptor (A) and one hydrogen bond donor (D). Screening of two small-molecule databases against this pharmacophore returned 620 hits with matching chemical features. Docking these against the ATP-binding site of the BTK kinase domain through a virtual screening workflow yielded 30 hits from which ultimately two natural compounds (two best scoring poses for each) were prioritized. Molecular dynamics simulations of these four docked complexes confirmed the stability of protein-ligand binding over a 200 ns time period, and thus their suitability for lead molecule development with further optimization and experimental testing. Of note, the pharmacophore model developed in this study would also be further useful for de novo drug design and virtual screening efforts on a larger scale. Graphical abstract Pharmacophore modeling and virtual screening in search of novel Bruton's tyrosine kinase inhibitors.

An Optimal Capillary Screen Cut-off of Thyroid Stimulating Hormone for Diagnosing Congenital Hypothyroidism: Data from a Pilot Newborn Screening Program in Delhi

OBJECTIVE

To determine an appropriate cut-off of capillary Thyroid stimulating hormone (TSH) for congenital hypothyroidism.

STUDY DESIGN

Cross-sectional.

PARTICIPANTS

174,000 neonates born in different hospitals of Delhi, India, from November 2014 to October 2016.

MAIN OUTCOME MEASURES

Correlation between initial and repeat capillary TSH level and subsequent venous free thyroxine (fT4) level.

RESULTS

102 newborns with initial/ repeat capillary TSH level of ≥20 mIU/L (n=174) were confirmed to have congenital hypothyroidism at mean (SD) age of 5 (4) days. A good correlation between capillary TSH level and confirmatory venous fT4 level and postnatal age of sampling was obtained (r -0.6, -0.4). The area under the ROC curve (AUC) was 0.81 (95%CI 0.75 to 0.88), indicating referral capillary TSH level of 20 mIU/L to be a good predictor of subsequent high venous TSH level.

CONCLUSIONS

A cut off of ≥20 mIU/L for capillary TSH screening beyond 24 hours of life is optimal in the Indian setting for deciding further recall and workup, keeping a balance between sensitivity and recall rate.

Rare variants in Protein tyrosine phosphatase, receptor type A (PTPRA) in schizophrenia: Evidence from a family based study

The contribution of both common and rare risk variants to the genetic architecture of schizophrenia (SZ) has been documented in genome-wide association studies, whole exome and whole genome sequencing approaches. As SZ is highly heritable and segregates in families, highly penetrant rare variants are more likely to be identified through analyses of multiply affected families. Further, much of the gene mapping studies in SZ have utilized individuals of Caucasian ancestry. Analysis of other ethnic groups may be informative. In this study, we aimed at identification of rare, penetrant risk variants utilizing whole exome sequencing (WES) in a three-generation Indian family with multiple members affected. Filtered data from WES, combined with in silico analyses revealed a novel heterozygous missense variant (NM_080841:c.1730C>G:p.T577R; exon18) in Protein tyrosine phosphatase, receptor type A (PTPRA 20p13). The variant was located in an evolutionarily conserved position and predicted to be damaging. Screening for variants in this gene in the WES data of an independent SZ cohort (n = 350) of matched ethnicity, identified five additional rare missense variants with MAF < 0.003, which were also predicted to be damaging. In conclusion, the rare missense variants in PTPRA identified in this study could confer risk for SZ. This has also derived support from concordant data from prior linkage and association, as well as animal studies which indicated a role for PTPRA in glutamate function.

Rare Variants in Tissue Inhibitor of Metalloproteinase 2 as a Risk Factor for Schizophrenia: Evidence From Familial and Cohort Analysis

Candidate gene and genome-wide association study based common risk variant identification is being complemented by whole exome sequencing (WES)/whole genome sequencing based rare variant discovery in elucidation of genetic landscape of schizophrenia (SZ), a common neuropsychiatric disorder. WES findings of de novo mutations in case-parent trios have further implied genetic etiology, but do not explain the high genetic risk in general populations. Conversely, WES in multiplex families may be an insightful strategy for the identification of highly penetrant rare variants in SZ and possibly enhance our understanding of disease biology. In this study, we analyzed a 5-generation Indian family with multiple members affected with SZ by WES. We identified a rare heterozygous missense variant (NM_003255: c.506C>T; p.Pro169Leu; MAF = 0.0001) in Tissue Inhibitor of Metalloproteinase 2 (TIMP2, 17q25.3) segregating with all 6 affected individuals but not with unaffected members. Linkage analysis indicated a maximum logarithm of the odds score of 1.8, θ = 0 at this locus. The variant was predicted to be damaging by various in silico tools and also disrupt the structural integrity by molecular dynamics simulations. WES based screening of an independent SZ cohort (n = 370) identified 4 additional rare missense variants (p.Leu20Met, p.Ala26Ser, p.Lys48Arg and p. Ile217Leu) and a splice variant rs540397728 (NM_003255:c.232-5T>C), also predicted to be damaging, increasing the likelihood of contribution of this gene to SZ risk. Extensive biochemical and knockout mouse studies suggesting involvement of TIMP2 in neurodevelopmental and behavioral deficits, together with genetic evidence for TIMP2 conferring SZ risk from this study may have possible implications for new therapeutics.

Status of Newborn Screening and Inborn Errors of Metabolism in India

Inborn errors of metabolism (IEM) are a heterogeneous group of genetic disorders that cause significant neonatal and infant mortality. Expanded newborn screening which detects these disorders at birth is the standard preventive strategy in most countries. Prospective studies to evaluate the impact of these in the Indian population are lacking. The imminent need to address this lacuna warrants a review of available pan India data, as well as efforts for a carefully conducted prospective assessment of the burden of IEM. Published data on IEM in the Indian population comprising universal prospective screening and screening in selected subgroups (patients admitted to pediatric/neonatal ICUs, patients with developmental delay/mental retardation) was collected through a systematic search. The primary focus was to get an estimate of the disease burden in the Indian population. A true prevalence of IEM in India is not available. The systematic review identifies and stratifies the various situations where IEM are found. Data collected by universal screening of the low risk population is essential to identify the true prevalence of IEM in India.

Genetics of ulcerative colitis: putting into perspective the incremental gains from Indian studies

Ulcerative colitis (UC), one of the two clinical subtypes of inflammatory bowel disease is perceived as a potential 'sleeping giant' in the Indian subcontinent. Clinical manifestation is overall believed to be the same across ethnic groups but overwhelming genetics from large European and fewer non-European studies have revealed shared as well as unique disease susceptibly signaturesbetween them, pointing to population specific differences at genomic and environmental levels. A systematic recount of the four major eras in UC genetics spanning earliest linkage analysis, cherry picked candidate gene association studies, unbiased genomewide association studies, their logical extension in trans-ethnic setting (Immunochip study), lastly whole exome sequencing efforts forrare variant burden; and lessons learnt thereof in context of genetically distinct Indian population was attempted in this review. Genetic heterogeneity manifesting at allelic/locus level across these approaches has been the consistent finding through the range of pan India studies. On the other hand, these salient findings also highlight the limitations of even the best of these genetic leadsfor prognostic/clinical application. The imminent need, therefore, for the UC research community to adopt newer approaches/tools with improved study design to (i) gain better insight into genetic/mechanistic basis of disease; (ii) identify biomarkers of immediate translational value; and (iii) develop new/alternate therapeutic options is emphasized at the end.

Determination of Dopamine-β-hydroxylase Activity in Human Serum Using UHPLC-PDA Detection

Dopamine-β-hydroxylase (DBH, EC 1.14.17.1) is an enzyme with implications in various neuropsychiatric and cardiovascular diseases and is a known drug target. There is a dearth of cost effective and fast method for estimation of activity of this enzyme. A sensitive UHPLC based method for the estimation of DBH activity in human sera samples based on separation of substrate tyramine from the product octopamine in 3 min is described here. In this newly developed protocol, a Solid Phase Extraction (SPE) sample purification step prior to LC separation, selectively removes interferences from the reaction cocktail with almost no additional burden on analyte recovery. The response was found to be linear with an r² = 0.999. The coefficient of variation for assay precision was < 10% and recovery > 90%. As a proof of concept, DBH activity in sera from healthy human volunteers (n = 60) and schizophrenia subjects (n = 60) were successfully determined using this method. There was a significant decrease in sera DBH activity in subjects affected by schizophrenia (p < 0.05) as compared to healthy volunteers. This novel assay employing SPE to separate octopamine and tyramine from the cocktail matrix may have implications for categorising subjects into various risk groups for Schizophrenia, Parkinson's disease as well as in high throughput screening of inhibitors.

Advances in the discovery of genetic risk factors for complex forms of neurodegenerative disorders: contemporary approaches, success, challenges and prospects

Neurodegenerative diseases constitute a large proportion of disorders in elderly, majority being sporadic in occurrence with ∼5-10% familial. A strong genetic component underlies the Mendelian forms but nongenetic factors together with genetic vulnerability contributes to the complex sporadic forms. Several gene discoveries in the familial forms have provided novel insights into the pathogenesis of neurodegeneration with implications for treatment. Conversely, findings from genetic dissection of the sporadic forms, despite large genomewide association studies and more recently whole exome and whole genome sequencing, have been limited. This review provides a concise account of the genetics that we know, the pathways that they implicate, the challenges that are faced and the prospects that are envisaged for the sporadic, complex forms of neurodegenerative diseases, taking four most common conditions, namely Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and Huntington disease as examples. Poor replication across studies, inability to establish genotype-phenotype correlations and the overall failure to predict risk and/or prevent disease in this group poses a continuing challenge. Among others, clinical heterogeneity emerges as the most important impediment warranting newer approaches. Advanced computational and system biology tools to analyse the big data are being generated and the alternate strategy such as subgrouping of case-control cohorts based on deep phenotyping using the principles of Ayurveda to overcome current limitation of phenotype heterogeneity seem to hold promise. However, at this point, with advances in discovery genomics and functional analysis of putative determinants with translation potential for the complex forms being minimal, stem cell therapies are being attempted as potential interventions. In this context, the possibility to generate patient derived induced pluripotent stem cells, mutant/gene/genome correction through CRISPR/Cas9 technology and repopulating the specific brain regions with corrected neurons, which may fulfil the dream of personalized medicine have been mentioned briefly. Understanding disease pathways/biology using this technology, with implications for development of novel therapeutics are optimistic expectations in the near future.

Functional characterisation of ADP ribosylation factor-like protein 15 in rheumatoid arthritis synovial fibroblasts

OBJECTIVES

ARL15 is a novel susceptibility gene identified in a recent GWAS in a north Indian rheumatoid arthritis (RA) cohort. However, the role of ARL15 or ARF family genes in RA aetiology remains unknown. Therefore, we aimed to i) establish the expression of ARL15 in rheumatoid arthritis synovial fibroblasts (RASF) and ii) its functional characterisation by assessing its effects on major inflammatory cytokines and interacting partners using a knockdown approach.

METHODS

RASF were cultured from synovial tissue obtained from RA patients (n=5) and osteoarthritis (OA) patients (n=3) serving as controls. Expression of ARL15, ARF1 and ARF6 in RASF was checked by semi-quantitative PCR and western blots; and altered expression of ARL15, if any, by induction of RASF with TNF using real-time PCR. The effect of ARL15 on the expression of adiponectin, adiponectin receptor I, IL6 and GAPDH and on cell mobility by invasion and migration assays were assessed by siRNA mediated gene knockdown.

RESULTS

Expression of ARL15, ARF1 and ARF6 was confirmed in RASF and OASF samples but ARL15 expression remained unaltered on TNF induction. Notably, ARL15 knockdown resulted in downregulation of IL6 and GAPDH, upregulation of adiponectin and adiponectin receptor I genes; and significant reduction in migration and invasion of RASF. Genemania showed significant interactions of ARL15 with genes responsible for insulin resistance and phospholipase D.

CONCLUSIONS

This first report on ARL15 expression in RASF and its likely role in inflammation and metabolic syndromes through a TNF independent pathway, encourages hypothesis-free studies to identify additional pathways underlying RA disease biology.

A simple phenotypic classification for celiac disease

Background/Aims

Celiac disease is a global health problem. The presentation of celiac disease has unfolded over years and it is now known that it can manifest at different ages, has varied presentations, and is prone to develop complications, if not managed properly. Although the Oslo definitions provide consensus on the various terminologies used in literature, there is no phenotypic classification providing a composite diagnosis for the disease.

Methods

Various variables identified for phenotypic classification included age at diagnosis, age at onset of symptoms, clinical presentation, family history and complications. These were applied to the existing registry of 1,664 patients at Dayanand Medical College and Hospital, Ludhiana, India. In addition, age was evaluated as below 15 and below 18 years. Cross tabulations were used for the verification of the classification using the existing data. Expert opinion was sought from both international and national experts of varying fields.

Results

After empirical verification, age at diagnosis was considered appropriate in between A1 (<18) and A2 (≥18). The disease presentation has been classified into 3 types–P1 (classical), P2 (non-classical) and P3 (asymptomatic). Complications were considered as absent (C0) or present (C1). A single phenotypic classification based on these 3 characteristics, namely age at the diagnosis, clinical presentation, and intestinal complications (APC classification) was derived.

Conclusions

APC classification (age at diagnosis, presentation, complications) is a simple disease explanatory classification for patients with celiac disease aimed at providing a composite diagnosis.

A preliminary study of association of genetic variants with early response to olanzapine in schizophrenia

BACKGROUND

Treatment response can be predicted in schizophrenia by DNA information in the drug metabolism pathways. This study aimed to examine clinical characteristics and genetic determinant (s) of early response to olanzapine treatment in schizophrenia using specified drug metabolizing genes.

MATERIALS AND METHODS

Consenting participants (n = 33) suffering from schizophrenia were diagnosed on Diagnostic Interview for Genetic Studies. Oral olanzapine was administered in an incremental dose up to 10 mg (2 weeks) and 20 mg (6 weeks). All participants were tested on Positive and Negative Syndrome Scale, Clinical Global Impressions, and Global Assessment of Functioning at 0, 2, and 6 weeks. Side effects were also evaluated. After 2 weeks, 11 (33.33%) fulfilled criteria for early response, whereas 17 (51.52%) responded at 6 weeks. We investigated the contribution of clinical factors and five polymorphisms (rs2740574, rs2470890, rs762551, rs3892097, and rs1065852) in predicting response to olanzapine at 2 and 6 weeks of treatment with a standard dose.

RESULTS

Severity of positive symptoms at baseline was associated with response at 2 weeks (P = 0.01) while higher scores on Scale for the Assessment of Negative Symptoms (SANS) at baseline was associated with response at both 2 (P = 0.04) and 6 weeks (P = 0.03). None of the five single nucleotide polymorphisms (SNPs) selected were significantly associated with response to olanzapine.

CONCLUSIONS

Olanzapine is an effective and safe drug. Positive and Negative Syndrome Scale positive score and SANS score were variably associated with response at 2 and/or 6 weeks. Replicate studies with bigger sample size are warranted for conclusive results in the Indian population for genetic association.

Possible role of rare variants in Trace amine associated receptor 1 in schizophrenia

Schizophrenia (SZ) is a chronic mental illness with behavioral abnormalities. Recent common variant based genome wide association studies and rare variant detection using next generation sequencing approaches have identified numerous variants that confer risk for SZ, but etiology remains unclear propelling continuing investigations. Using whole exome sequencing, we identified a rare heterozygous variant (c.545G>T; p.Cys182Phe) in Trace amine associated receptor 1 gene (TAAR1 6q23.2) in three affected members in a small SZ family. The variant predicted to be damaging by 15 prediction tools, causes breakage of a conserved disulfide bond in this G-protein-coupled receptor. On screening this intronless gene for additional variant(s) in ~800 sporadic SZ patients, we identified six rare protein altering variants (MAF<0.001) namely p.Ser47Cys, p.Phe51Leu, p.Tyr294Ter, p.Leu295Ser in four unrelated north Indian cases (n=475); p.Ala109Thr and p.Val250Ala in two independent Caucasian/African-American patients (n=310). Five of these variants were also predicted to be damaging. Besides, a rare synonymous variant was observed in SZ patients. These rare variants were absent in north Indian healthy controls (n=410) but significantly enriched in patients (p=0.036). Conversely, three common coding SNPs (rs8192621, rs8192620 and rs8192619) and a promoter SNP (rs60266355) tested for association with SZ in the north Indian cohort were not significant (P>0.05). TAAR1 is a modulator of monoaminergic pathways and interacts with AKT signaling pathways. Substantial animal model based pharmacological and functional data implying its relevance in SZ are also available. However, this is the first report suggestive of the likely contribution of rare variants in this gene to SZ.

Pedigree Analysis of Familial Primary Concomitant Horizontal Strabismus in Northern India

PURPOSE

Familial clustering of common forms of primary strabismus like esotropia (ET) and exotropia (XT) is observed in a proportion of the strabismus cohort. The genetic components of this remain unidentified. Linkage studies have demonstrated susceptibility locus for primary strabismus at the STBMS1 locus on 7p22.1 as well as other loci on 4q28.3 and 7q31.2. Recently next generation sequencing (NGS) technology has emerged as a powerful tool in discovery genomics and a large number of novel disease-causing variants are being reported. In this study, we recruited informative families for subsequent genetic analysis for disease-causing variant identification.

METHODS

All consecutive families with two or more affected members with primary concomitant horizontal strabismus were prospectively recruited at the ophthalmic outpatients department (OPD) of Lady Hardinge Medical College, New Delhi, from August 2014 to February 2017. Detailed phenotypic evaluation and pedigree documentation was performed.

RESULTS

Of the 39 recruited families of north Indian origin, 18 families each had affected family members demonstrating either ET or XT. 100% concordance of the phenotype in the affected family members was observed in these families. While vertical transmission was observed in 17/18 families with XT, 7 with ET had affected members across one generation, 2 demonstrated consanguineous pedigree, and 2 comprised identical twin families. In 3 families, a combination of ET and XT was noted. This comprised one family with the ET and XT patients being from 2 separate arms of the family related by marriage, one family where one sibling had XT and the other had ET, and another family where the maternal aunt of the affected proband with ET had XT.

CONCLUSIONS

Subjects with familial primary concomitant strabismus recruited in this study may provide a valuable resource to unravel the genetic determinants of this condition, which is a common disorder of early childhood with high ophthalmic morbidity.

Characterization of SNPs in the dopamine-β-hydroxylase gene providing new insights into its structure-function relationship

Dopamine-β-hydroxylase (DBH, EC 1.14.17.1), an oxido-reductase that catalyses the conversion of dopamine to norepinephrine, is largely expressed in sympathetic neurons and adrenal medulla. Several regulatory and structural variants in DBH associated with various neuropsychiatric, cardiovascular diseases and a few that may determine enzyme activity have also been identified. Due to paucity of studies on functional characterization of DBH variants, its structure-function relationship is poorly understood. The purpose of the study was to characterize five non-synonymous (ns) variants that were prioritized either based on previous association studies or Sorting Tolerant From Intolerant (SIFT) algorithm. The DBH ORF with wild type (WT) and site-directed mutagenized variants were transfected into HEK293 cells to generate transient and stable lines expressing these variant enzymes. Activity was determined by UPLC-PDA and corresponding quantity by MRM^HR on a TripleTOF 5600 MS respectively of spent media from stable cell lines. Homospecific activity computed for the WT and variant proteins showed a marginal decrease in A318S, W544S and R549C variants. In transient cell lines, differential secretion was observed in the case of L317P, W544S and R549C. Secretory defect in L317P was confirmed by localization in ER. R549C exhibited both decreased homospecific activity and differential secretion. Of note, all the variants were seen to be destabilizing based on in silico folding analysis and molecular dynamics (MD) simulation, lending support to our experimental observations. These novel genotype-phenotype correlations in this gene of considerable pharmacological relevance have implications for dopamine-related disorders.

Validation of Polymerase Chain Reaction-Based Assay to Detect Actual Number of CGG Repeats in FMR1 Gene in Indian Fragile X Syndrome Patients

Molecular genetic testing for fragile X (FX) is complicated due to the large variation in the size of CGG expansion. The aim of this study was to apply this new technique using AmplideX FMR1 PCR assay, which is considered a better diagnostic tool for detecting expanded alleles in Indian population. The primary objective was to identify the carrier status of females and to correlate the instability of premutation alleles in females with the repeat sizes. 24 children with FX based on rapid PCR and 29 female relatives of these patients were included. Out of the 29 females screened, those whose child (or children) was affected by FX, were all premutation carriers confirming their role in transmission. The smallest PM allele that expanded into FM in the next generation was 78 repeats and the smallest PM allele detected was 63 repeats, and when transmitted from mother to offspring remained in the premutation range. In 4 families, the repeat size of the allele reduced from PM to normal repeat numbers in their daughters and in 1 case to borderline PM range. Thus, apart from the reduced turnaround time, this PCR based assay offers advantage by its sensitivity to detect CGG repeats in the intermediate region and lower range of premutation alleles. It also provides added information of AGG interruptions, which may have an impact on the counseling of women with intermediate and PM alleles.

Evaluation of cytochrome P4502E1 polymorphisms in healthy adult Western Indians and patients with antituberculous drug-induced hepatotoxicity

Objectives:

Cytochrome P4502E1 (CYP2E1) is involved in the metabolism of isoniazid and the mediation of its hepatotoxicity. It exhibits genetic polymorphism in humans. This study evaluated the polymorphism of CYP2E1 in adult healthy Western Indians and patients on antituberculous drugs by phenotyping and genotyping.

Methods:

A 500 mg single dose of chlorzoxazone (CZX) was administered to 136 healthy adult Western Indian participants. Venous blood samples 2 h postdose were analyzed for the levels of CZX and 6-hydroxy CZX, and the metabolic ratio (MR) was calculated to determine the extent of rapid and poor metabolizers using probit plot analysis. Patients on antituberculous drugs who had raised the liver enzymes or clinical symptoms of hepatotoxicity were also recruited. Genotyping for CYP2E1 * 5B allele was performed by polymerase chain reaction – rapid fragment length polymorphism technique.

Results:

A total of 139 healthy participants were enrolled, of which the final analysis consisted of data from 136 participants for genotyping and 137 for phenotyping. Only 1 participant had reported mild drowsiness 2 h postdose, and no other adverse events were observed. The median (range) MR of population was 0.2 (0.1–4.0), and no polymorphisms were detected using phenotype data. A total of 134/136 (98.5%) had c1/c1 genotype and 1/136 each (0.75%) had c1/c2 and c2/c2 genotypes, respectively. Of the 2/136 participants harboring c2 allele, one had MR of 0.1 (c1/c2) and another had 0.5 (c2/c2). A total of 25 cases of antituberculous drug-induced hepatotoxicity and 50 control patients were recruited, of which finally 22 cases and 49 controls were available for evaluation. All the cases had c1/c1 genotype while 42/49 (85.7%) controls had c1/c1, 6/49 (12.2%) had c1/c2, and 1/49 (2.1%) had c2/c2 genotype and the crude odds ratio was 7.9 (0.4, 145.6).

Conclusions:

A background prevalence of CYP2E1*B polymorphism and their activity in Western Indian population was observed. The study suggests no association between the CYP2E1 genotyping with antituberculous drug-induced hepatotoxicity.

Shared and unique common genetic determinants between pediatric and adult celiac disease

BACKGROUND

Based on age of presentation, celiac disease (CD) is categorised as pediatric CD and adult CD. It however remains unclear if these are genetically and/or phenotypically distinct disorders or just different spectrum of the same disease. We therefore explored the common genetic components underlying pediatric and adult CD in a well characterized north Indian cohort.

METHODS

A retrospective analysis of children (n = 531) and adult (n = 871) patients with CD between January 2001 and December 2010 was done. The database included basic demographic characteristics, clinical presentations, associated diseases and complications, if any. The genotype dataset was acquired for children (n = 217) and adult CD patients (n = 340) and controls (n = 736) using Immunochip. Association analysis was performed using logistic regression model to identify susceptibility genetic variants.

RESULTS

The predominant form of CD was classical CD in both pediatric and adult CD groups. There was remarkable similarity between pediatric and adult CD except for quantitative differences between the two groups such as female preponderance, non-classical presentation, co-occurrence of other autoimmune diseases being more common amongst adult CD. Notably, same HLA-DQ2 and -DQ8 haplotypes were established as the major risk factors in both types of CD. In addition, a few suggestively associated (p < 5 × 10(-4)) non-HLA markers were identified of which only ANK3 (rs4948256-A; rs10994257-T) was found to be shared and explain risk for ~45 % of CD patients with HLA allele.

DISCUSSION

Overall phenotypic similarity between pediatric and adult CD groups can be explained by contribution of same HLA risk alleles. Different non-HLA genes/loci with minor risk seem to play crucial role in disease onset and extra intestinal manifestation of CD. None of the non-HLA risk variants reached genome-wide significance, however most of them were shown to have functional implication to disease pathogenesis. Functional relevance of our findings needs to be investigated to address clinical heterogeneity of CD.

CONCLUSIONS

This present study is the first comparative study based on common genetic markers to suggest that CD in pediatric age group and in adults are the spectrum of the same disease with novel and shared genetic risk determinants. Follow-up fine mapping studies with larger study cohorts are warranted for further genetic investigation.

Association study of MiRSNPs with schizophrenia, tardive dyskinesia and cognition

MicroRNAs (miRNAs) bind to 3'UTRs of genes and negatively regulate their expression. With ~50% of miRNAs expressing in the brain, they play an important role in neuronal development, plasticity, cognition and neurological disorders. Conserved miRNA targets are present in >60% genes in humans and are under evolutionary pressure to maintain pairing with miRNA. However, such binding may be affected by genetic variant(s) in the target sites (MiRSNPs), thereby altering gene expression. Differential expression of a large number of genes in postmortem brains of schizophrenia (SZ) patients compared to controls has been documented. Thus studying the role of MiRSNPs which are underinvestigated in SZ becomes attractive. We systematically selected 35 MiRSNPs with predicted functional relevance in 3'UTRs of genes shown previously to be associated with SZ, genotyped and tested their association with disease, using independent discovery and replication samples (total n=1017 cases; n=1073 controls). We also explored genetic associations with two sets of quantitative traits, namely tardive dyskinesia (TD) and cognitive functions disrupted in SZ in subsets of the study cohort. In the primary analysis, a significant association of MiRSNP rs7430 at PPP3CC was observed with SZ in the discovery and the replication samples [discovery: P=0.01; OR (95% CI) 1.24 (1.04-1.48); replication: P=0.03; OR (95% CI) 1.20 (1.02-1.43)]. In the exploratory analyses, five SNPs were nominally associated with TD (P values 0.04-0.004). Separately, 12 SNPs were associated with one or more of the eight cognitive domains (P values 0.05-0.003). These associations, particularly the SNP at PPP3CC merit further investigations.

Association of polymorphisms of CYP2C9, CYP2C19, and ABCB1, and activity of P-glycoprotein with response to anti-epileptic drugs

BACKGROUND AND OBJECTIVE

Epilepsy, the most common neurological disorder, has treatment failure rate of 20 to 25%. Inter-individual variability in drug response can be attributed to genetic polymorphism in genes encoding different drug metabolizing enzymes, drug transporters (P-gp), and enzymes involved in sodium channel biosynthesis. The present study attempted to evaluate association of polymorphisms of CYP2C9, CYP2C19, and ABCB1, and P-gp activity with treatment response in patients with epilepsy.

MATERIALS AND METHODS

Patients with epilepsy on phenytoin and/or phenobarbital and/or carbamazepine were categorized into responders and non-responders as per the International League Against Epilepsy. Plasma drug concentration was estimated by high-performance liquid chromatography. P-gp activity was measured by flow cytometry using rhodamine efflux. The polymerase chain reaction (PCR-RFLP) was used to study polymorphisms of ABCB1 (C3435T), CYP2C9 (416 C > T, and 1061 A > T), and CYP2C19 (681 G > A and 636 G > A).

RESULTS

Of total 117 patients enrolled in this study, genotype data was available for 115 patients. P-gp activity was higher in non-responders (n = 68) compared to responders (n = 47) (P<0.001). No association of 416 C > T and 1061 A > T in CYP2C9 or 681 G > A and 636 G > A in CYP2C19 was observed with response phenotype in genotypic analysis. Significant genotypic (odds ratio, OR = 4.5; 95% CI, 1.04 to 20.99) and allelic association (OR = 1.73; 95% CI, 1.02 to 2.95) was observed with ABCB1 C3435T and response phenotype.

CONCLUSIONS

The response to antiepileptics seems to be modulated by C3435T in ABCB1 or P-gp activity. At present, role of other genetic factors in treatment responsiveness in epilepsy appears limited, warranting analysis in a larger cohort.

Identification of critical variants within SLC44A4, an ulcerative colitis susceptibility gene identified in a GWAS in north Indians

SLC44A4 is one of the seven novel susceptibility genes that were discovered in the first ever genome-wide association study (GWAS) on ulcerative colitis (UC) in the genetically distinct north Indians. This gene seems to be functionally relevant to disease biology as it may contribute to the associated phenotype of Vitamin B1 deficiency among UC patients, hence playing a role in disease pathogenesis. A large number of single-nucleotide polymorphisms (SNPs) are known to be distributed throughout this gene, but the functional status of most are not known. Thus, an extensive investigation of structural and regulatory variants within this gene was undertaken in this study to identify the critical variants amongst them using a combination of fine mapping, in silico and in vitro approaches. A few intronic SNPs were predicted to have regulatory roles on the basis of in silico analysis, suggesting that they may be the critical variants within SLC44A4. This highlights the importance of this gene in UC biology, thus confirming the finding of the GWAS and also warranting additional studies.

Abstract P067: Novel Antagonists of Dopamine-β-hydroxylase Identified and Validated Through Structure Based Approach to Combat Hypertension

Human dopamine β-hydroxylase (hDBH), expressed in noradrenergic nerve terminals of nervous system and in chromaffin cells of adrenal medulla, is a key constituent of catecholamine biosynthetic pathway. DBH inhibition has been shown to help the treatment of hypertension, cardiac hypertrophy and cardiac heart failure, which are major causes of mortality and morbidity worldwide. Existing hDBH inhibitors are too few, often result in side effects and are frequently non-responsive to specific population. Since no three-dimensional structure existed for full-length hDBH, structure based rational drug design was elusive till date, an issue to which we provided solution lately by building an experimentally validated in silico model for hDBH. The model was used in Autodock, Glide SP and XP software for structure based virtual screening against small molecule databases from NCI, USA. The docked structures were scored using Autodock, X-Score and Prime MMGBSA. Thus, 69 compounds were identified as prospective inhibitors of DBH, which were then tested in vitro against human serum DBH and its nearly identical homologue, bovine DBH (586 of 617 amino acids homologous), with known inhibitors nepicastat and disulfiram as positive controls. Three lead molecules UDSC171, UDSC180 and UDSC142 were discovered in the process as potent inhibitors of DBH with IC50s of 1μM, 5.5μM and 18μM, respectively. The binding of the inhibitors to the enzyme were validated using fluorescence and CD spectroscopy as well as ITC, revealing KD values in the range of 100nm to 1μM. In silico pharmacokinetic analysis indicated the molecules to be latest generation of DBH inhibitors having very high cell permeability and inability to cross the blood brain barrier. High doses (up to 50μM) of the lead compounds showed acceptable cellular tolerance against HEK 293 cell line and insignificant hemo-toxicities against human RBCs. Hence, in vivo evaluation of the lead molecules were done in small model systems like C. elegans and D. melanogaster reconfirming their nontoxic properties up to 15μM doses. These three leads are now being tested in cardiac hypertrophy and hypertension rat models with exciting preliminary results.

Genome-wide association scan in north Indians reveals three novel HLA-independent risk loci for ulcerative colitis

OBJECTIVE

Over 100 ulcerative colitis (UC) loci have been identified by genome-wide association studies (GWASs) primarily in Caucasians (CEUs). Many of them have weak effects on disease susceptibility, and the bulk of the heritability cannot be ascribed to these loci. Very little is known about the genetic background of UC in non-CEU groups. Here we report the first GWAS on UC in a genetically distinct north Indian (NI) population.

DESIGN

A genome-wide scan was performed on 700 cases and 761 controls. 18 single-nucleotide polymorphisms (SNPs) (p<5×10(-5)) were genotyped in an independent cohort of 733 cases and 1148 controls. A linear mixed model was used for case-control association tests.

RESULTS

Seven novel human leucocyte antigen (HLA)-independent SNPs from chromosome 6, located in 3.8-1, BAT2, MSH5, HSPA1L, SLC44A4, CFB and NOTCH4, exceeded p<5×10(-8) in the combined analysis. To assess the independent biological contribution of such genes from the extended HLA region, we determined the percentage alternative pathway activity of complement factor B (CFB), the top novel hit. The activity was significantly different (p=0.01) between the different genotypes at rs12614 in UC cases. Transethnic comparisons revealed a shared contribution of a fraction of UC risk genes between NI and CEU populations, in addition to genetic heterogeneity.

CONCLUSIONS

This study shows varying contribution of the HLA region to UC in different populations. Different environmental exposures and the characteristic genetic structure of the HLA locus across ethnic groups collectively make it amenable to the discovery of causative alleles by transethnic resequencing. This may lead to an improved understanding of the molecular mechanisms underlying UC.