Whole-genome sequencing in autism identifies hot spots for de novo germline mutation.

De novo mutation plays an important role in autism spectrum disorders (ASDs). Notably, pathogenic copy number variants (CNVs) are characterized by high mutation rates. We hypothesize that hypermutability is a property of ASD genes and may also include nucleotide-substitution hot spots. We investigated global patterns of germline mutation by whole-genome sequencing of monozygotic twins concordant for ASD and their parents. Mutation rates varied widely throughout the genome (by 100-fold) and could be explained by intrinsic characteristics of DNA sequence and chromatin structure. Dense clusters of mutations within individual genomes were attributable to compound mutation or gene conversion. Hypermutability was a characteristic of genes involved in ASD and other diseases. In addition, genes impacted by mutations in this study were associated with ASD in independent exome-sequencing data sets. Our findings suggest that regional hypermutation is a significant factor shaping patterns of genetic variation and disease risk in humans.

Frequency and Complexity of De Novo Structural Mutation in Autism.

Genetic studies of autism spectrum disorder (ASD) have established that de novo duplications and deletions contribute to risk. However, ascertainment of structural variants (SVs) has been restricted by the coarse resolution of current approaches. By applying a custom pipeline for SV discovery, genotyping, and de novo assembly to genome sequencing of 235 subjects (71 affected individuals, 26 healthy siblings, and their parents), we compiled an atlas of 29,719 SV loci (5,213/genome), comprising 11 different classes. We found a high diversity of de novo mutations, the majority of which were undetectable by previous methods. In addition, we observed complex mutation clusters where combinations of de novo SVs, nucleotide substitutions, and indels occurred as a single event. We estimate a high rate of structural mutation in humans (20%) and propose that genetic risk for ASD is attributable to an elevated frequency of gene-disrupting de novo SVs, but not an elevated rate of genome rearrangement.

Duplications of the neuropeptide receptor gene VIPR2 confer significant risk for schizophrenia.

Rare copy number variants (CNVs) have a prominent role in the aetiology of schizophrenia and other neuropsychiatric disorders. Substantial risk for schizophrenia is conferred by large (>500-kilobase) CNVs at several loci, including microdeletions at 1q21.1 (ref. 2), 3q29 (ref. 3), 15q13.3 (ref. 2) and 22q11.2 (ref. 4) and microduplication at 16p11.2 (ref. 5). However, these CNVs collectively account for a small fraction (2-4%) of cases, and the relevant genes and neurobiological mechanisms are not well understood. Here we performed a large two-stage genome-wide scan of rare CNVs and report the significant association of copy number gains at chromosome 7q36.3 with schizophrenia. Microduplications with variable breakpoints occurred within a 362-kilobase region and were detected in 29 of 8,290 (0.35%) patients versus 2 of 7,431 (0.03%) controls in the combined sample. All duplications overlapped or were located within 89 kilobases upstream of the vasoactive intestinal peptide receptor gene VIPR2. VIPR2 transcription and cyclic-AMP signalling were significantly increased in cultured lymphocytes from patients with microduplications of 7q36.3. These findings implicate altered vasoactive intestinal peptide signalling in the pathogenesis of schizophrenia and indicate the VPAC2 receptor as a potential target for the development of new antipsychotic drugs.

Helicobacter pylori in gastric malignancies.

Helicobacter pylori infection remains common worldwide and is significantly associated with gastric adenocarcinoma and gastric mucosa-associated lymphoid tissue (MALT)lymphoma. This article reviews recent developments in the field of H. pylori with an emphasis on mechanisms of carcinogenesis, and the bacterial, environmental and host factors that may alter risk of developing gastric cancer or gastric MALT lymphoma. The topic of eradication of H. pylori to prevent the development of malignancy and the possibility of a vaccine against H. pylori are also explored.

Anaemia among Patients of Heart Failure in a Tertiary Care Centre of Nepal: A Descriptive Cross-sectional Study.

INTRODUCTION: Anaemia is an important comorbidity common in patients with heart failure and is associated with poor clinical status and worse outcomes. In Nepal few studies have evaluated anaemia amongst patients suffering from heart failure. We intended to find out the prevalence of anaemia in patients with heart failure in a tertiary care centre. METHODS: This is a descriptive cross-sectional study conducted among patients of heart failure presenting to tertiary care hospital in eastern Nepal from April 2017 to January 2018. Ethical approval was taken from the Institutional Review Committee of a tertiary care centre (reference number: IRC/0842/016). Using the convenience sampling method, 100 patients were enrolled in the study. Blood samples from the patients were taken for haemoglobin and serum iron studies. Data was analysed using Statistical Package for Social Sciences version 11. Point estimate at 95% Confidence Interval was calculated, with frequency and percentage. RESULTS: Among 100 patients with heart failure, 82 (82%) (74.47-89.53 at 95% Confidence Interval) had anaemia. Mean haemoglobin level of the study population was 10.40±2.73 g/dl. Fifty four (54%) of patients had iron deficiency status irrespective of presence or absence of anaemia. CONCLUSIONS: Prevalence of anaemia among patients of heart failure in our study was found to be higher than various other homologous international studies.

Human Poisoning due to Delphinium Species in the Himalayan Region of Nepal: A Case Report.

The Delphinium species herb, common name 'Nirmasi' in Nepal, is one of the community level flower herbs used as medicinal ingredients in various clinical problems in Manang District and other Himalayan parts of Nepal. Roots of the plants from the genus Delphinium have been used for a long time for headache, epilepsy, mania, paralysis, rheumatism, toothache, and various types of pain. However, many species of Delphinium are poisonous and look quite similar in morphology to the beneficial ones. As a result, accidental poisoning is common. Poisoning due to these plants results in symptoms due to gastric irritation, competitive neuromuscular blockade, and cardiotoxicity caused by various alkaloids present in them. We report here a case of poisoning due to Delphinium species ingestion presenting as hypotension and bradycardia managed successfully with symptomatic treatment.

Colorectal cancer is a leading cause of cancer incidence and mortality among adults younger than 50†years in the USA: a SEER-based analysis with comparison to other young-onset cancers.

Colorectal cancer (CRC) incidence and mortality are rising among young adults. Our aim was to contrast the relative incidence and mortality of CRC to other common cancers among young adults in the USA. We used Surveillance, Epidemiology, and End Results registry data to compare cancer site-specific and age-specific mortality and incident rates for adults younger than age 50. We summarized extracted data, both overall, and stratified by sex. We found CRC was the third leading cause of cancer death among adults younger than age 50, after breast and lung cancer (1.67 cases per 100,000). Among young women, CRC was the fourth leading cause of cancer death (1.51 per 100,000). Among young men, CRC was the second leading cause of cancer death (1.82 cases per 100,000). CRC was the second most incident cancer among young adults for men and women combined. Among men, CRC was the second most incident cancer after age 30, with 4.9, 9.0, 16.4, and 30.8 cases per 100,000 for ages 30-34, 35-39, 40-44, and 45-49 years, respectively. Among women, CRC incidence was similar with 4.2, 7.6, 15.3, and 25.9 cases per 100,000 for ages 30-34, 35-39, 40-44, and 45-49 years, respectively. These results show that CRC is a leading cause of cancer incidence and mortality among young adults in the USA, relative to other cancers. Given trends toward increasing rates of CRC among young adults, strategies for identifying individuals at risk for young-onset CRC who might benefit from early age of screening initiation merit investigation.

High frequencies of de novo CNVs in bipolar disorder and schizophrenia.

While it is known that rare copy-number variants (CNVs) contribute to risk for some neuropsychiatric disorders, the role of CNVs in bipolar disorder is unclear. Here, we reasoned that a contribution of CNVs to mood disorders might be most evident for de novo mutations. We performed a genome-wide analysis of de novo CNVs in a cohort of 788 trios. Diagnoses of offspring included bipolar disorder (n = 185), schizophrenia (n = 177), and healthy controls (n = 426). Frequencies of de novo CNVs were significantly higher in bipolar disorder as compared with controls (OR = 4.8 [1.4,16.0], p = 0.009). De novo CNVs were particularly enriched among cases with an age at onset younger than 18 (OR = 6.3 [1.7,22.6], p = 0.006). We also confirmed a significant enrichment of de novo CNVs in schizophrenia (OR = 5.0 [1.5,16.8], p = 0.007). Our results suggest that rare spontaneous mutations are an important contributor to risk for bipolar disorder and other major neuropsychiatric diseases.

Microduplications of 16p11.2 are associated with schizophrenia.

Recurrent microdeletions and microduplications of a 600-kb genomic region of chromosome 16p11.2 have been implicated in childhood-onset developmental disorders. We report the association of 16p11.2 microduplications with schizophrenia in two large cohorts. The microduplication was detected in 12/1,906 (0.63%) cases and 1/3,971 (0.03%) controls (P = 1.2 x 10(-5), OR = 25.8) from the initial cohort, and in 9/2,645 (0.34%) cases and 1/2,420 (0.04%) controls (P = 0.022, OR = 8.3) of the replication cohort. The 16p11.2 microduplication was associated with a 14.5-fold increased risk of schizophrenia (95% CI (3.3, 62)) in the combined sample. A meta-analysis of datasets for multiple psychiatric disorders showed a significant association of the microduplication with schizophrenia (P = 4.8 x 10(-7)), bipolar disorder (P = 0.017) and autism (P = 1.9 x 10(-7)). In contrast, the reciprocal microdeletion was associated only with autism and developmental disorders (P = 2.3 x 10(-13)). Head circumference was larger in patients with the microdeletion than in patients with the microduplication (P = 0.0007).

Rare structural variants disrupt multiple genes in neurodevelopmental pathways in schizophrenia.

Schizophrenia is a devastating neurodevelopmental disorder whose genetic influences remain elusive. We hypothesize that individually rare structural variants contribute to the illness. Microdeletions and microduplications >100 kilobases were identified by microarray comparative genomic hybridization of genomic DNA from 150 individuals with schizophrenia and 268 ancestry-matched controls. All variants were validated by high-resolution platforms. Novel deletions and duplications of genes were present in 5% of controls versus 15% of cases and 20% of young-onset cases, both highly significant differences. The association was independently replicated in patients with childhood-onset schizophrenia as compared with their parents. Mutations in cases disrupted genes disproportionately from signaling networks controlling neurodevelopment, including neuregulin and glutamate pathways. These results suggest that multiple, individually rare mutations altering genes in neurodevelopmental pathways contribute to schizophrenia.