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Boston, MA, United States

Massachusetts General Hospital is the original and largest teaching hospital of Harvard Medical School and a biomedical research facility located in the West End neighborhood of Boston, Massachusetts. It is the third oldest general hospital in the United States and the oldest and largest hospital in New England with 950 beds. Massachusetts General Hospital conducts the largest hospital-based research program in the world, with an annual research budget of more than $750 million. It is currently ranked as the #2 hospital in the United States by U.S. News & World Report. Wikipedia.

Background Findings from family and twin studies suggest that genetic contributions to psychiatric disorders do not in all cases map to present diagnostic categories. We aimed to identify specifi c variants underlying genetic eff ects shared between the fi ve disorders in the Psychiatric Genomics Consortium: autism spectrum disorder, attention defi cit-hyperactivity disorder, bipolar disorder, major depressive disorder, and schizophrenia. Methods We analysed genome-wide single-nucleotide polymorphism (SNP) data for the fi ve disorders in 33 332 cases and 27 888 controls of European ancestory. To characterise allelic eff ects on each disorder, we applied a multinomial logistic regression procedure with model selection to identify the best-fi tting model of relations between genotype and phenotype. We examined cross-disorder eff ects of genome-wide signifi cant loci previously identifi ed for bipolar disorder and schizophrenia, and used polygenic risk-score analysis to examine such eff ects from a broader set of common variants. We undertook pathway analyses to establish the biological associations underlying genetic overlap for the fi ve disorders. We used enrichment analysis of expression quantitative trait loci (eQTL) data to assess whether SNPs with cross-disorder association were enriched for regulatory SNPs in post-mortem brain-tissue samples. Findings SNPs at four loci surpassed the cutoff for genome-wide signifi cance (p< 5×10-8) in the primary analysis: regions on chromosomes 3p21 and 10q24, and SNPs within two L-type voltage-gated calcium channel subunits, CACNA1C and CACNB2. Model selection analysis supported eff ects of these loci for several disorders. Loci previously associated with bipolar disorder or schizophrenia had variable diagnostic specifi city. Polygenic risk scores showed cross-disorder associations, notably between adult-onset disorders. Pathway analysis supported a role for calcium channel signalling genes for all fi ve disorders. Finally, SNPs with evidence of cross-disorder association were enriched for brain eQTL markers. Interpretation Our fi ndings show that specifi c SNPs are associated with a range of psychiatric disorders of childhood onset or adult onset. In particular, variation in calcium-channel activity genes seems to have pleiotropic eff ects on psychopathology. These results provide evidence relevant to the goal of moving beyond descriptive syndromes in psychiatry, and towards a nosology informed by disease cause. Source

Ananthakrishnan A.N.,Massachusetts General Hospital
Nature Reviews Gastroenterology and Hepatology | Year: 2015

IBD, comprising Crohn's disease and ulcerative colitis, is a chronic immunologically mediated disease at the intersection of complex interactions between genetics, environment and gut microbiota. Established high-prevalence populations of IBD in North America and Europe experienced the steepest increase in incidence towards the second half of the twentieth century. Furthermore, populations previously considered 'low risk' (such as in Japan and India) are witnessing an increase in incidence. Potentially relevant environmental influences span the spectrum of life from mode of childbirth and early-life exposures (including breastfeeding and antibiotic exposure in infancy) to exposures later on in adulthood (including smoking, major life stressors, diet and lifestyle). Data support an association between smoking and Crohn's disease whereas smoking cessation, but not current smoking, is associated with an increased risk of ulcerative colitis. Dietary fibre (particularly fruits and vegetables), saturated fats, depression and impaired sleep, and low vitamin D levels have all been associated with incident IBD. Interventional studies assessing the effects of modifying these risk factors on natural history and patient outcomes are an important unmet need. In this Review, the changing epidemiology of IBD, mechanisms behind various environmental associations and interventional studies to modify risk factors and disease course are discussed. © 2015 Macmillan Publishers Limited. Source

Hamilos D.L.,Massachusetts General Hospital
Journal of Allergy and Clinical Immunology | Year: 2014

There has been considerable investigation of host-microbial interactions in patients with chronic rhinosinusitis (CRS) in hopes of elucidating mechanisms of disease and better treatment. Most attention has been paid to bacterial infection and potential underlying defects in innate immunity. Bacterial biofilm is present in most patients with CRS undergoing surgical intervention, and its presence is associated with more severe disease and worse surgical outcomes. A role for viral or fungal infection in patients with CRS is less clear. There is no evidence for a primary defect in mucociliary clearance in most patients with CRS. Decreased levels of certain antimicrobial proteins, most notably lactoferrin, have been found in sinus secretions, whereas levels of other antimicrobial proteins have been found to be normal. No primary defects in Toll-like receptors have been found in patients with CRS, although a 50% reduced expression of Toll-like receptor 9 was reported in patients with recalcitrant nasal polyps. A polymorphism in a bitter taste receptor was recently associated with refractory CRS and persistent Pseudomonas aeruginosa infection. A downregulation of innate immunity by maladaptive TH2 tissue inflammation has also been described in patients with recalcitrant nasal polyps, suggesting a link to persistent infection. To date, an effective means of restoring host-microbial balance and mitigating disease in patients with CRS remains elusive. © 2013 American Academy of Allergy, Asthma and Immunology. Source

Scadden D.T.,Massachusetts General Hospital | Scadden D.T.,Harvard Stem Cell Institute
Cell | Year: 2014

No metazoan cell survives on its own, absent the signals and support of its milieu. For multicellular life with specialized tissues to persist, organization is everything and so defining the association of position with cell state is critical to understanding how tissues function, maintain, and repair. This review focuses specifically on place for progenitor and stem cells. Especially emphasized are hematopoietic cells that balance free movement and stable position and where concepts of regulatory interrelationships have been shown with some precision. It reviews classical and emerging concepts of the niche, particularly considering how niche functions may participate in neoplastic disease. © 2014 Elsevier Inc. Source

Hamilos D.L.,Massachusetts General Hospital
Journal of Allergy and Clinical Immunology | Year: 2011

Chronic rhinosinusitis (CRS) affects 12.5% of the US population. On epidemiologic grounds, some association has been found between CRS prevalence and air pollution, active cigarette smoking, secondhand smoke exposure, perennial allergic rhinitis, and gastroesophageal reflux. The majority of pediatric and adult patients with CRS are immune competent. Data on genetic associations with CRS are still sparse. Current consensus definitions subclassify CRS into CRS without nasal polyposis (CRSsNP), CRS with nasal polyposis (CRSwNP), and allergic fungal rhinosinusitis (AFRS). Evaluation and medical management of CRS has been the subject of several recent consensus reports. The highest level of evidence for treatment for CRSsNP exists for saline lavage, intranasal steroids, and long-term macrolide antibiotics. The highest level of evidence for treatment of CRSwNP exists for intranasal steroids, systemic glucocorticoids, and topical steroid irrigations. Aspirin desensitization is beneficial for patients with aspirin-intolerant CRSwNP. Sinus surgery followed by use of systemic steroids is recommended for AFRS. Other modalities of treatment, such as antibiotics for patients with purulent infection and antifungal drugs for patients with AFRS, are potentially useful despite a lack of evidence from controlled treatment trials. The various modalities of medical treatment are reviewed in the context of recent consensus documents and the author's personal experience. © 2011 American Academy of Allergy, Asthma & Immunology. Source

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