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The ductus arteriosus (DA) is a unique fetal vascular shunt, which allows blood to bypass the developing lungs in utero. After birth, changes in complex signaling pathways lead to constriction and permanent closure of the DA. The persistent patency of the DA (PDA) is a common disorder in preterm infants, yet the underlying causes of PDA are not fully defined. Although limits on the availability of human DA tissues prevent comprehensive studies on the mechanisms of DA function, mouse models have been developed that reveal critical pathways in DA regulation. Over 20 different transgenic models of PDA in mice have been described, with implications for human DA biology. Similarly, we enumerate 224 human single‐gene syndromes that are associated with PDA, including a small subset that consistently feature PDA as a prominent phenotype. Comparison and functional analyses of these genes provide insight into DA development and identify key regulatory pathways that may serve as potential therapeutic targets for the management of PDA. [ABSTRACT FROM AUTHOR]

The author discusses bioethics and argues that the pace of genomic screening is too rapid and without proper consideration for the impact on the global clinical ecosystem.

The combination of family-based linkage analysis with high-throughput sequencing is a powerful approach to identifying rare genetic variants that contribute to genetically heterogeneous syndromes. Using parametric multipoint linkage analysis and whole exome sequencing, we have identified a gene responsible for microcephaly (MCP), severe visual impairment, intellectual disability, and short stature through the mapping of a homozygous nonsense alteration in a multiply-affected consanguineous family. This gene, DIAPH1, encodes the mammalian Diaphanous-related formin (mDia1), a member of the diaphanous-related formin family of Rho effector proteins. Upon the activation of GTP-bound Rho, mDia1 generates linear actin filaments in the maintenance of polarity during adhesion, migration, and division in immune cells and neuroepithelial cells, and in driving tangential migration of cortical interneurons in the rodent. Here, we show that patients with a homozygous nonsense DIAPH1 alteration (p.Gln778*) have MCP as well as reduced height and weight. diap1 (mDia1 knockout (KO))-deficient mice have grossly normal body and brain size. However, our histological analysis of diap1 KO mouse coronal brain sections at early and postnatal stages shows unilateral ventricular enlargement, indicating that this mutant mouse shows both important similarities as well as differences with human pathology. We also found that mDia1 protein is expressed in human neuronal precursor cells during mitotic cell division and has a major impact in the regulation of spindle formation and cell division. [ABSTRACT FROM AUTHOR]

Background Oliver–McFarlane syndrome is characterised by trichomegaly, congenital hypopituitarism and retinal degeneration with choroidal atrophy. Laurence–Moon syndrome presents similarly, though with progressive spinocerebellar ataxia and spastic paraplegia and without trichomegaly. Both recessively inherited disorders have no known genetic cause. Methods Whole-exome sequencing was performed to identify the genetic causes of these disorders. Mutations were functionally validated in zebrafish pnpla6 morphants. Embryonic expression was evaluated via in situ hybridisation in human embryonic sections. Human neurohistopathology was performed to characterise cerebellar degeneration. Enzymatic activities were measured in patient-derived fibroblast cell lines. Results Eight mutations in six families with Oliver–McFarlane or Laurence–Moon syndrome were identified in the PNPLA6 gene, which encodes neuropathy target esterase (NTE). PNPLA6 expression was found in the developing human eye, pituitary and brain. In zebrafish, the pnpla6 curly-tailed morphant phenotype was fully rescued by wild-type human PNPLA6 mRNA and not by mutation-harbouring mRNAs. NTE enzymatic activity was significantly reduced in fibroblast cells derived from individuals with Oliver–McFarlane syndrome. Intriguingly, adult brain histology from a patient with highly overlapping features of Oliver–McFarlane and Laurence–Moon syndromes revealed extensive cerebellar degeneration and atrophy. Conclusions Previously, PNPLA6 mutations have been associated with spastic paraplegia type 39, Gordon–Holmes syndrome and Boucher–Neuhäuser syndromes. Discovery of these additional PNPLA6-opathies further elucidates a spectrum of neurodevelopmental and neurodegenerative disorders associated with NTE impairment and suggests a unifying mechanism with diagnostic and prognostic importance. [ABSTRACT FROM AUTHOR]

Objective To assess the risk of adverse fetal outcomes following exposure to individual immunosuppressive drugs in pregnant women with chronic immune-mediated diseases. Methods Health plan data were obtained from the Tennessee Medicaid and Kaiser Permanente Northern California and Southern California claims databases, with linkage to both vital records and medical records. Women with inflammatory arthropathies, those with systemic lupus erythematosus, and those with inflammatory bowel disease who filled prescriptions for immunosuppressive treatments during pregnancy were included. Major congenital malformations, fetal deaths, and life-threatening neonatal complications were identified from the electronic data and validated with medical record review. Results The cohort included 608 infants, including 437 with exposure to immunosuppressive drugs during the mother's pregnancy (402 during the first trimester, and 35 during the second and third trimester only) and 171 whose mothers filled prescriptions for immunosuppressive treatments before, but not during, pregnancy. There were 25 pregnancies (4.1% of the cohort) with confirmed major congenital malformations, and 10 fetal deaths (1.6% of the cohort). Among 113 preterm infants with exposures during pregnancy, 23 (20.4%) had life-threatening neonatal complications, and among 485 term infants, 10 (2.1%) had life-threatening complications. Compared to the reference group (treatment before, but not during, pregnancy), the risk ratios (RRs) for adverse fetal outcomes associated with immunosuppressive treatments (by exposure category) during pregnancy included the following: methotrexate (RR 1.39, 95% confidence interval [95% CI] 0.43-4.53), tumor necrosis factor inhibitors (RR 0.98, 95% CI 0.38-2.55), hydroxychloroquine (RR 1.33, 95% CI 0.69-2.55), and other immunosuppressive medications (RR 0.98, 95% CI 0.48-1.98). Conclusion In this study, there was no evidence of a large increase in risk of adverse fetal outcomes from first-trimester exposure to immunosuppressive medications, although the confidence intervals for the risk ratios were wide. Further studies will be needed as use of these medications increases over time. [ABSTRACT FROM AUTHOR]

Obesity disproportionately affects Latina women. Common genetic variants are convincingly associated with body mass index (BMI) and may be used to create genetic risk scores (GRS) for obesity that could define genetically influenced forms of obesity and alter response to clinical trial interventions. The objective of this study was (1) to identify the frequency and effect size of common obesity genetic variants in Latina women; (2) to determine the clinical utility of a GRS for obesity with Latina women participating in a community-based clinical trial. DNA from 85 Latina women was genotyped for eight genetic variants previously associated with BMI in Caucasians, but not yet assessed in Latina populations. The main outcome measure was the correlation of GRS (sum of eight risk alleles) with BMI, waist circumference, and percent body fat. A majority (83%) of participants had a BMI ≥25. Frequency of loci near FTO, MC4R, and GNPDA2 were lower in Latinas than Caucasians. Association of each locus with BMI was lower in Latinas compared to Caucasians with no significant correlations with BMI. We conclude that an eight locus GRS has no clinical utility for explaining obesity or predicting response to intervention in Latina women participating in a clinical trial. Clin Trans Sci 2011; Volume 4: 323-327 [ABSTRACT FROM AUTHOR]

Background: Parental consanguinity is a risk factor for congenital heart disease (CHD) worldwide, suggesting that a recessive inheritance model may contribute substantially to CHD. In Bangalore, India, uncle-niece and first cousin marriages are common, presenting the opportunity for an international study involving consanguinity mapping of structural CHD. We sought to explore the recessive model of CHD by conducting a genome-wide linkage analysis utilizing high-density oligonucleotide microarrays and enrolling 83 CHD probands born to unaffected consanguineous parents. Methodology/Principal Findings: In this linkage scan involving single nucleotide polymorphism (SNP) markers, the threshold for genome-wide statistical significance was set at the standard log-of-odds (LOD) score threshold of 3.3, corresponding to 1995:1 odds in favor of linkage. We identified a maximal single-point LOD score of 3.76 (5754:1 odds) implicating linkage of CHD with the major allele (G) of rs1055061 on chromosome 14 in the HOMEZ gene, a ubiquitously expressed transcription factor containing leucine zipper as well as zinc finger motifs. Re-sequencing of HOMEZ exons did not reveal causative mutations in Indian probands. In addition, genotyping of the linked allele (G) in 325 U.S. CHD cases revealed neither genotypic nor allele frequency differences in varied CHD cases compared to 605 non-CHD controls. Conclusions/Significance: Despite the statistical power of the consanguinity mapping approach, no single gene of major effect could be convincingly identified in a clinically heterogeneous sample of Indian CHD cases born to consanguineous parents. However, we are unable to exclude the possibility that noncoding regions of HOMEZ may harbor recessive mutations leading to CHD in the Indian population. Further research involving large multinational cohorts of patients with specific subtypes of CHD is needed to attempt replication of the observed linkage peak on chromosome 14. In addition, we anticipate that a targeted re-sequencing approach may complement linkage analysis in future studies of recessive mutation detection in CHD. [ABSTRACT FROM AUTHOR]

Information about several topics discussed at the National Institutes of Health (NIH) State-of-the-Science Conference Statement in the U.S. is presented. Topics include family history for common diseases, health improvement, and medical research. The panel of the conference outlined several guide questions related to the above mentioned topics and concluded that family history plays an important role in medicine practice and can prompt positive lifestyle changes.

Background: Many candidate genes have been reported to be risk factors for acute coronary syndrome (ACS), but their impact on clinical prognosis following ACS is unknown. Methods: We examined the association of putative genetic risk factors with 3-year post-ACS mortality in 811 ACS survivors at university-affiliated hospitals in Kansas City, Missouri. Through a systematic literature search, we first identified genetic variants reported as susceptibility factors for atherosclerosis or ACS. Restricting our analysis to whites, so as to avoid confounding from racial admixture, we genotyped ACS cases for 89 genetic variants in 72 genes, and performed individual Kaplan-Meier survival analyses. We then performed Cox regression to create multivariate risk prediction models that further minimized potential confounding. Results: Of 89 variants tested, 16 were potentially associated with mortality (P < 0.1 for all), of which 6 were significantly associated (P < 0.05) with mortality following ACS. While these findings are not more than what would be expected by chance (P = 0.28), even after Bonferroni correction and adjustment for traditional cardiac risk factors, the IRS1 972Arg variant association (P = 0.001) retained borderline statistical significance (P < 0.1). Conclusion: With the possible exception of IRS1, we conclude that multiple candidate genes were not associated with post-ACS mortality in our patient cohort. Because of power limitations, the 16 gene variants with P values < 0.1 may warrant further study. Our data do not support the hypothesis that the remaining 73 genes have substantial, clinically significant association with mortality after an ACS. [ABSTRACT FROM AUTHOR]

The article presents the results of a literature review conducted by the authors that examined the putative genetic risk factors for acute coronary syndromes. The authors genotyped white patients with acute coronary syndromes and controls for variants in genes in an attempt to duplicate associations of the genetic variants with risk factors for acute coronary syndromes that had previously been reported. The authors found that none of the genetic variants tested were risk factors for acute coronary syndromes. The authors state that the previously reported studies linking the genetic variations to acute coronary syndromes need to be replicated before their findings are put into clinical practice.

Gilles de la Tourette syndrome (GTS) is a potentially debilitating neuropsychiatric disorder defined by the presence of both vocal and motor tics. Despite evidence that this and a related phenotypic spectrum, including chronic tics (CT) and Obsessive Compulsive Disorder (OCD), are genetically mediated, no gene involved in disease etiology has been identified. Chromosomal abnormalities have long been proposed to play a causative role in isolated cases of GTS spectrum phenomena, but confirmation of this hypothesis has yet to be forthcoming. We describe an i(18q21.1-q22.2) inversion in a patient with CT and OCD. We have fine mapped the telomeric aspect of the rearrangement to within I Mb of a previously reported 18q22 breakpoint that cosegregated in a family with GTS and related phenotypes. A comprehensive characterization of this genomic interval led to the identification of two transcripts, neither of which was found to be structurally disrupted. Analysis of the epigenetic characteristics of the region demonstrated a significant increase in replication asynchrony in the patient compared to controls, with the inverted chromosome showing delayed replication timing across at least a 500-kb interval. These findings are consistent with long-range functional dysregulation of one or more genes in the region. Our data support a link between chromosomal aberrations and epigenetic mechanisms in GTS and suggest that the study of the functional consequences of balanced chromosomal rearrangements is warranted in patients with phenotypes of interest, irrespective of the findings regarding structurally disrupted transcripts. [ABSTRACT FROM AUTHOR]

A reply is presented by Drs. Thomas M. Morgan, Harlan M. Krumholz and John A. Pertus to letters to the editor about their article "Nonvalidation of reported genetic risk factors for acute coronary syndrome in a large-scale replication study."