Medical Sciences Commons^™

Statistical Genetic Approaches To Investigate Genotype-By-Environment Interaction: Review And Novel Extension Of Models, Vincent P. Diego, Eron G. Manusov, Marcio Almeida, Sandra Laston, David Ortiz, John Blangero, Sarah Williams-Blangero

School of Medicine Publications and Presentations

Statistical genetic models of genotype-by-environment (G×E) interaction can be divided into two general classes, one on G×E interaction in response to dichotomous environments (e.g., sex, disease-affection status, or presence/absence of an exposure) and the other in response to continuous environments (e.g., physical activity, nutritional measurements, or continuous socioeconomic measures). Here we develop a novel model to jointly account for dichotomous and continuous environments. We develop the model in terms of a joint genotype-by-sex (for the dichotomous environment) and genotype-by-social determinants of health (SDoH; for the continuous environment). Using this model, we show how a depression variable, as measured by the …

Ongoing Study Of The Association Of Apoe Gene Polymorphisms With Cognitive Impairment In The Rio Grande Valley Hispanic Population, Jaime Miguel L. Saveron, Daniela Gamez, Chun Xu

Research Symposium

Background: Alzheimer's disease (AD), a prevalent neurodegenerative disorder, exhibits a significant genetic component. In addition, mild cognitive impairment (MCI) is a key risk factor for AD. While certain demographic factors and genetic variants associated with AD and cognitive impairment have been identified in non-Hispanic populations, limited research exists on this subject within the Hispanic population, particularly in the Rio Grande Valley. This study aims to investigate the relationship between the APOE gene, specifically its ε4 allele, and cognitive impairment in the Hispanic population of the Rio Grande Valley.

Methods: A total of 269 Hispanic subjects, aged 60 and above, with …

Functional Characterization Of The Ipsc Generated Hepatocytes Using Genome-Wide Transcriptomic Analysis, Ashley Ikwuezunma, Erica De Leon, Ana C. Leandro, Joanne E. Curran, John Blangero, Satish Kumar

Research Colloquium

Advances in iPSC technologies now allow us to consider non-invasive large-scale in-vitro disease modeling experiments on disease appropriate cell types in human subjects to better understand human disease pathophysiology, disease genetics and to develop better diagnostic and therapeutic technologies. We performed differential gene expression and functional annotation analysis using genome wide mRNA sequencing data to evaluate the functional and disease modeling potential of iPSC generated hepatocytes. Following the criteria moderated t statistics FDR corrected p-value ≤ 0.05 and fold change-absolute ≥ 2.0, 7,246 genes/transcripts were significantly differentially expressed iPSCs and hepatocytes. The 3,791 of these DE genes/transcripts were significantly …

Gene By Environment Interaction And Metabolic-Associated Fatty Liver Disease In Mexican American Patients With Depression, Khalid Sheikh, Vincent P. Diego, Sandra L. Laston, Eron G. Manusov, Sarah Williams-Blangero, John Blangero

Research Colloquium

Knowledge of genetic and environmental (G x E) interaction effects on metabolic-associated fatty liver disease (MAFLD) is limited. The purpose of this study was to examine the impact of G x E interaction effects on MAFLD in Mexican Americans in the Rio Grande Valley (RGV). The environment examined was depression as measured by the Beck Depression Inventory-II (BDI-II). We examined potential G x E interaction in the phenotypic expression of MAFLD, including hepatic steatosis and hepatic fibrosis, using variance component models and likelihood-based statistical inference. Significant G x E interactions were identified for hepatic fibrosis x BDI-II. These findings provide …

Variant Of Fii Gene Plays A Critical Role In Coagulation Potential In Mexican-Americans, Hoang Anh T. Nguyen, Shuchita Vijay Jhaveri, Marcio A. Almeida, Vincent P. Diego, Satish Kumar, Juan M. Peralta, Joanne E. Curran, Bernadette W. Luu, Donna M. Lehman, Ralph A. Defronzo, Laura Almasy, Sarah Williams-Blangero, Ravi Duggirala, John Blangero, Tom Howard

Research Symposium

Background: Disruption in the balance between coagulation and bleeding can result in varying phenotypes such as hypercoagulability and can lead to the development of cardiovascular disease. In our study utilizing extended families of Mexican-Americans from South Texas, we performed a search for protein-altering variants influencing coagulation potential.

Methods: Mexican-Americans in the study were genotyped using Illumina-(human)-exome-24 chip to screen for protein-altering variants. Variants were analyzed for their association with FII activity, aPTT, and PT. Linear-mixed-model analysis was performed to estimate trait heritabilities and to interrogate single nucleotide variations (SNV) for evidence of genetic association. To control for multiple testing, associations …

Dpyd Pathogenic Variants Associated With Fluoropyrimidines Toxicity, Diana Cristina Pérez-Ibave, Noé Israel Oliva-García, Irasema Ramos-Martínez, Francisco Javier Villarreal Alvarado, Valeria Jimena Gómez Ordaz, Jonatán Isaí Cortes Alfaro, Carlos Horacio Burciaga-Flores, Juan Francisco González-Guerrero, Oscar Vidal-Gutiérrez, Maria De Lourdes Garza-Rodriguez

Research Symposium

Background: Genetic variants in dihydropyrimidine dehydrogenase gene (DPYD) coding for the key enzyme (DPD) of fluoropyrimidines (FPs) catabolism. DPYD contributes to the development of severe FPs-related toxicity, and pathogenic DPYD variants detection reduces side effects and complications associated with FP-toxicity. The allelic frequency of these variants in the Mexican population is currently unknown.

Methods: The study was carried out at the Centro Universitario Contra el Cáncer (CUCC) of the Universidad Autónoma de Nuevo León (UANL) in Monterrey México. Genomic DNA was isolated from 154 subjects using the QIAamp DNA Blood Midi kit (QIAGEN) following the manufacturer's recommendations. We …

Genotype-By-Socioeconomic Status Interaction Influences Heart Disease Risk Scores And Carotid Artery Thickness In Mexican Americans: The Predominant Role Of Education In Comparison To Household Income And Socioeconomic Index, Vincent P. Diego, Eron G. Manusov, Xi Mao, Joanne E. Curran, Harald H. H. Goring, Marcio Almeida, Michael Mahaney, Juan M. Peralta, John Blangero, Sarah Williams-Blangero

School of Medicine Publications and Presentations

Background: Socioeconomic status (SES) is a potent environmental determinant of health. To our knowledge, no assessment of genotype-environment interaction has been conducted to consider the joint effects of socioeconomic status and genetics on risk for cardiovascular disease (CVD). We analyzed Mexican American Family Studies (MAFS) data to evaluate the hypothesis that genotype-by-environment interaction (GxE) is an important determinant of variation in CVD risk factors.

Methods: We employed a linear mixed model to investigate GxE in Mexican American extended families. We studied two proxies for CVD [Pooled Cohort Equation Risk Scores/Framingham Risk Scores (FRS/PCRS) and carotid artery intima-media thickness (CA-IMT)] in …

Potential Mirna Biomarkers And Therapeutic Targets For Early Atherosclerotic Lesions, Genesio M. Karere, Jeremy P. Glenn, Ge Li, Ayati Konar, John L. Vandeberg, Laura A. Cox

School of Medicine Publications and Presentations

Identification of potential therapeutic targets and biomarkers indicative of burden of early atherosclerosis that occur prior to advancement to life-threatening unstable plaques is the key to eradication of CAD prevalence and incidences. We challenged 16 baboons with a high cholesterol, high fat diet for 2 years and evaluated early-stage atherosclerotic lesions (fatty streaks, FS, and fibrous plaques, FP) in formalin-fixed common iliac arteries (CIA). We used small RNA sequencing to identify expressed miRNAs in CIA and in baseline blood samples of the same animals. We found 412 expressed miRNAs in CIA and 356 in blood samples. Eight miRNAs (miR-7975, -486-5p, …

Multi-Ancestry Transcriptome-Wide Association Analyses Yield Insights Into Tobacco Use Biology And Drug Repurposing, Fang Cheng, Xingyan Wang, Seon-Kyeong Jang, Bryan C. Quach, J. Dylan Weissenkampen, Chachrit Khunsriraksakul, Lina Yang, John Blangero, Joanne E. Curran, Ravindranath Duggirala, Juan M. Peralta

School of Medicine Publications and Presentations

Most transcriptome-wide association studies (TWASs) so far focus on European ancestry and lack diversity. To overcome this limitation, we aggregated genome-wide association study (GWAS) summary statistics, whole-genome sequences and expression quantitative trait locus (eQTL) data from diverse ancestries. We developed a new approach, TESLA (multi-ancestry integrative study using an optimal linear combination of association statistics), to integrate an eQTL dataset with a multi-ancestry GWAS. By exploiting shared phenotypic effects between ancestries and accommodating potential effect heterogeneities, TESLA improves power over other TWAS methods. When applied to tobacco use phenotypes, TESLA identified 273 new genes, up to 55% more compared with …

Powerful, Scalable And Resource-Efficient Meta-Analysis Of Rare Variant Associations In Large Whole Genome Sequencing Studies, Xihao Li, Corbin Quick, Hufeng Zhou, Sheila M. Gaynor, John Blangero, Joanne E. Curran, Ravindranath Duggirala, Harald H. H. Goring, Michael Mahaney, Juan M. Peralta

School of Medicine Publications and Presentations

Meta-analysis of whole genome sequencing/whole exome sequencing (WGS/WES) studies provides an attractive solution to the problem of collecting large sample sizes for discovering rare variants associated with complex phenotypes. Existing rare variant meta-analysis approaches are not scalable to biobank-scale WGS data. Here we present MetaSTAAR, a powerful and resource-efficient rare variant meta-analysis framework for large-scale WGS/WES studies. MetaSTAAR accounts for relatedness and population structure, can analyze both quantitative and dichotomous traits and boosts the power of rare variant tests by incorporating multiple variant functional annotations. Through meta-analysis of four lipid traits in 30,138 ancestrally diverse samples from 14 studies of …

Shared Brain And Genetic Architectures Between Mental Health And Physical Activity, Wei Zhang, Sarah E. Paul, Anderson M. Winkler, Ryan Bogdan, Janine D. Bijsterbosch

School of Medicine Publications and Presentations

Physical activity is correlated with, and effectively treats various forms of psychopathology. However, whether biological correlates of physical activity and psychopathology are shared remains unclear. Here, we examined the extent to which the neural and genetic architecture of physical activity and mental health are shared. Using data from the UK Biobank (N = 6389), we applied canonical correlation analysis to estimate associations between the amplitude and connectivity strength of subnetworks of three major neurocognitive networks (default mode, DMN; salience, SN; central executive networks, CEN) with accelerometer-derived measures of physical activity and self-reported mental health measures (primarily of depression, anxiety …

The Genetic Contribution To Solving The Cocktail-Party Problem, Samuel R. Mathias, Emma Knowles, Josephine Mollon, Amanda Rodrigue, Mary K. Woolsey, Rene L. Olvera, Juan M. Peralta, Satish Kumar, Harald H. H. Goring, Ravi Duggirala, Joanne E. Curran, John Blangero, David C. Glahn

School of Medicine Publications and Presentations

Communicating in everyday situations requires solving the cocktail-party problem, or segregating the acoustic mixture into its constituent sounds and attending to those of most interest. Humans show dramatic variation in this ability, leading some to experience real-world problems irrespective of whether they meet criteria for clinical hearing loss. Here, we estimated the genetic contribution to cocktail-party listening by measuring speech-reception thresholds (SRTs) in 425 people from large families and ranging in age from 18 to 91 years. Roughly half the variance of SRTs was explained by genes (h 2 = 0.567). The genetic correlation between SRTs and hearing thresholds …

Identification Of Healthspan-Promoting Genes In Caenorhabditis Elegans Based On A Human Gwas Study, Nadine Saul, Ineke Dhondt, Mikko Kuokkanen, Markus Perola, Clara Verschuuren, Brecht Wouters, Henrik Von Chrzanowski, Winnok H. De Vos, Liesbet Temmerman, Walter Luyten

School of Medicine Publications and Presentations

To find drivers of healthy ageing, a genome-wide association study (GWAS) was performed in healthy and unhealthy older individuals. Healthy individuals were defined as free from cardiovascular disease, stroke, heart failure, major adverse cardiovascular event, diabetes, dementia, cancer, chronic obstructive pulmonary disease (COPD), asthma, rheumatism, Crohn’s disease, malabsorption or kidney disease. Six single nucleotide polymorphisms (SNPs) with unknown function associated with ten human genes were identified as candidate healthspan markers. Thirteen homologous or closely related genes were selected in the model organism C. elegans for evaluating healthspan after targeted RNAi-mediated knockdown using pathogen resistance, muscle integrity, chemotaxis index and the …

Comparing Empirical Kinship Derived Heritability For Imaging Genetics Traits In The Uk Biobank And Human Connectome Project, Si Gao, Brian Donohue, Kathryn S. Hatch, Shuo Chen, Tianzhou Ma, Yizhou Ma, Mark D. Kvarta, Bhim M. Adhikari, Neda Jahanshad, John Blangero

School of Medicine Publications and Presentations

Imaging genetics analyses use neuroimaging traits as intermediate phenotypes to infer the degree of genetic contribution to brain structure and function in health and/or illness. Coefficients of relatedness (CR) summarize the degree of genetic similarity among subjects and are used to estimate the heritability – the proportion of phenotypic variance explained by genetic factors. The CR can be inferred directly from genome-wide genotype data to explain the degree of shared variation in common genetic polymorphisms (SNP-heritability) among related or unrelated subjects. We developed a central processing and graphics processing unit (CPU and GPU) accelerated Fast and Powerful Heritability Inference …

Multi-Phenotype Genome-Wide Association Studies Of The Norfolk Island Isolate Implicate Pleiotropic Loci Involved In Chronic Kidney Disease, Ngan K. Tran, Rodney A. Lea, Samuel Holland, Quan Nguyen, Arti M. Raghubar, Heidi G. Sutherland, Miles C. Benton, Nicholas B. Blackburn, Joanne E. Curran, John Blangero

School of Medicine Publications and Presentations

Chronic kidney disease (CKD) is a persistent impairment of kidney function. Genome-wide association studies (GWAS) have revealed multiple genetic loci associated with CKD susceptibility but the complete genetic basis is not yet clear. Since CKD shares risk factors with cardiovascular diseases and diabetes, there may be pleiotropic loci at play but may go undetected when using single phenotype GWAS. Here, we used multi-phenotype GWAS in the Norfolk Island isolate (n = 380) to identify new loci associated with CKD. We performed a principal components analysis on different combinations of 29 quantitative traits to extract principal components (PCs) representative of multiple …

Determinants Of Penetrance And Variable Expressivity In Monogenic Metabolic Conditions Across 77,184 Exomes, Julia K. Goodrich, Moriel Singer-Berk, Rachel Son, Abigail Sveden, Jordan Wood, Eleina England, Joanne B. Cole, John Blangero, Ben Weisburd, Ravi Duggirala

School of Medicine Publications and Presentations

Hundreds of thousands of genetic variants have been reported to cause severe monogenic diseases, but the probability that a variant carrier develops the disease (termed penetrance) is unknown for virtually all of them. Additionally, the clinical utility of common polygenetic variation remains uncertain. Using exome sequencing from 77,184 adult individuals (38,618 multi-ancestral individuals from a type 2 diabetes case-control study and 38,566 participants from the UK Biobank, for whom genotype array data were also available), we apply clinical standard-of-care gene variant curation for eight monogenic metabolic conditions. Rare variants causing monogenic diabetes and dyslipidemias display effect sizes significantly larger than …

Robust, Flexible, And Scalable Tests For Hardy-Weinberg Equilibrium Across Diverse Ancestries, Alan M. Kwong, Thomas W. Blackwell, Jonathon Lefaive, Mariza De Andrade, John Barnard, Kathleen C. Barnes, John Blangero

School of Medicine Publications and Presentations

Traditional Hardy-Weinberg equilibrium (HWE) tests (the χ2 test and the exact test) have long been used as a metric for evaluating genotype quality, as technical artifacts leading to incorrect genotype calls often can be identified as deviations from HWE. However, in datasets comprised of individuals from diverse ancestries, HWE can be violated even without genotyping error, complicating the use of HWE testing to assess genotype data quality. In this manuscript, we present the Robust Unified Test for HWE (RUTH) to test for HWE while accounting for population structure and genotype uncertainty, and evaluate the impact of population heterogeneity and genotype …

Sequencing Of 53,831 Diverse Genomes From The Nhlbi Topmed Program, Daniel Taliun, Daniel N. Harris, Michael D. Kessler, Jedidiah Carlson, John Blangero, Joanne E. Curran, Michael C. Mahaney, Harald H. H. Goring, Ravindranath Duggirala, Juan M. Peralta

School of Medicine Publications and Presentations

The Trans-Omics for Precision Medicine (TOPMed) programme seeks to elucidate the genetic architecture and biology of heart, lung, blood and sleep disorders, with the ultimate goal of improving diagnosis, treatment and prevention of these diseases. The initial phases of the programme focused on whole-genome sequencing of individuals with rich phenotypic data and diverse backgrounds. Here we describe the TOPMed goals and design as well as the available resources and early insights obtained from the sequence data. The resources include a variant browser, a genotype imputation server, and genomic and phenotypic data that are available through dbGaP (Database of Genotypes and …

Heritability Of Ocular Traits In Hispanics, Aaron T. Gomez, Gladys E. Maestre, Jesus D. Melgarejo, Vincent P. Diego, Nicholas B. Blackburn, Juan B. Yepez, Michele Petitto, Felipe A. Murati, Rosa V. Pirela, Carlos A. Chavez, Winston Lee, Lama A. Al-Aswad, Rando Allikmets, C. Gustavo De Moraes, Matthew P. Johnson, Joseph D. Terwilliger, Joseph H. Lee, John Blangero

MEDI 9331 Scholarly Activities Clinical Years

Purpose: The burden of glaucoma disease among Hispanics is significantly higher than in their white counterparts. It remains unclear to what extent these differences are determined by genetic factors in Hispanics. We therefore examined a highly inbred family population-based cohort in Venezuela to estimate the proportion of genetic contribution of ocular traits relevant to glaucoma disease.

Methods: A subset of 67 participants ≥40y from the Maracaibo Aging Study (MAS) with family pedigree were randomly included. The papillary retinal nerve fiber layer (RNFL) and macular thickness were measured with Spectralis Domain-OCT. Heritability analyses (h², expressed as %) …

Inherited Causes Of Clonal Haematopoiesis In 97,691 Whole Genomes, Alexander G. Bick, Joshua S. Weinstock, Satish K. Nandakumar, Charles P. Fulco, Erik L. Bao, Seyedeh M. Zekavat, Mindy D. Szeto, Juan M. Peralta, Joanne E. Curran, John Blangero

School of Medicine Publications and Presentations

Age is the dominant risk factor for most chronic human diseases, but the mechanisms through which ageing confers this risk are largely unknown1. The age-related acquisition of somatic mutations that lead to clonal expansion in regenerating haematopoietic stem cell populations has recently been associated with both haematological cancer2,3,4 and coronary heart disease5—this phenomenon is termed clonal haematopoiesis of indeterminate potential (CHIP)6. Simultaneous analyses of germline and somatic whole-genome sequences provide the opportunity to identify root causes of CHIP. Here we analyse high-coverage whole-genome sequences from 97,691 participants of diverse …

Updated Genes, Lifestyles, And Their Interactions For Human Longevity, Brenda Bin Su, Alexis Villafranca, Chunxiang Mao, Stephanie Hernandez, Stephanie Lozano, Masoud M. Zarei, Kesheng Wang, Saraswathy Nair, Chun Xu

Health & Biomedical Sciences Faculty Publications and Presentations

Healthy aging is the prolonging of optimal wellbeing during the progressive decline in physiological functions that are necessary for survival. Two important components of aging include an individual’s genetic makeup and lifestyle choices such as diet and exercise. Genetic factors are responsible for the functional physiology of the body including cell maintenance, metabolism and apoptosis. The individual effects of genes and lifestyle choices on aging are reported mainly in Caucasian populations, with very limited studies in minority populations. In this review, we included the effects of genes and environment and the interaction between them on aging in Hispanic population in …

Benchmarking Relatedness Inference Methods With Genome-Wide Data From Thousands Of Relatives, Monica D. Ramstetter, Thomas D. Dyer, Donna M. Lehman, Joanne E. Curran, Ravindranath Duggirala, John Blangero, Jason G. Mezey, Amy L. Williams

School of Medicine Publications and Presentations

Inferring relatedness from genomic data is an essential component of genetic association studies, population genetics, forensics, and genealogy. While numerous methods exist for inferring relatedness, thorough evaluation of these approaches in real data has been lacking. Here, we report an assessment of 12 state-of-the-art pairwise relatedness inference methods using a data set with 2485 individuals contained in several large pedigrees that span up to six generations. We find that all methods have high accuracy (92–99%) when detecting first- and second-degree relationships, but their accuracy dwindles to76% of relative pairs. Overall, the most accurate methods are Estimation of Recent Shared Ancestry …

A Large Genome-Wide Association Study Of Age-Related Macular Degeneration Highlights Contributions Of Rare And Common Variants, Lars G. Fritsche, Wilmar Igl, Jessica N. Cooke Bailey, Felix Grassmann, Sebanti Sengupta, Jennifer L. Bragg-Gresham, Kathryn P. Burdon, Scott J. Hebbring, Matthew P. Johnson, John Blangero

School of Medicine Publications and Presentations

Advanced age-related macular degeneration (AMD) is the leading cause of blindness in the elderly with limited therapeutic options. Here, we report on a study of >12 million variants including 163,714 directly genotyped, most rare, protein-altering variant. Analyzing 16,144 patients and 17,832 controls, we identify 52 independently associated common and rare variants (P < 5×10–8) distributed across 34 loci. While wet and dry AMD subtypes exhibit predominantly shared genetics, we identify the first signal specific to wet AMD, near MMP9 (difference-P = 4.1×10–10). Very rare coding variants (frequency < 0.1%) in CFH, CFI, and TIMP3 suggest causal roles for these genes, as does a splice variant in SLC16A8. Our results support the hypothesis that rare coding variants can pinpoint causal genes within known genetic loci and illustrate …

Lipidomic Risk Score Independently And Cost-Effectively Predicts Risk Of Future Type 2 Diabetes: Results From Diverse Cohorts, Manju Mamtani, Hemant Kulkarni, Gerard Wong, Jacquelyn M. Weir, Christopher K. Barlow, Thomas D. Dyer, Laura Almasy, Michael C. Mahaney, Anthony G. Comuzzie, David C. Glahn, Sarah Williams-Blangero, Ravindranath Duggirala, John Blangero, Joanne E. Curran

School of Medicine Publications and Presentations

Background: Detection of type 2 diabetes (T2D) is routinely based on the presence of dysglycemia. Although disturbed lipid metabolism is a hallmark of T2D, the potential of plasma lipidomics as a biomarker of future T2D is unknown. Our objective was to develop and validate a plasma lipidomic risk score (LRS) as a biomarker of future type 2 diabetes and to evaluate its cost-effectiveness for T2D screening.

Methods: Plasma LRS, based on significantly associated lipid species from an array of 319 lipid species, was developed in a cohort of initially T2D-free individuals from the San Antonio Family Heart Study (SAFHS). The …

Shared Genetic Variance Between Obesity And White Matter Integrity In Mexican Americans, Elena A. Spieker, Peter Kochunov, Laura M. Rowland, Emma Sprooten, Anderson M. Winkler, Rene L. Olvera, Laura Almasy, Ravi Duggirala, Peter T. Fox, John Blangero, David C. Glahn, Joanne E. Curran

School of Medicine Publications and Presentations

Obesity is a chronic metabolic disorder that may also lead to reduced white matter integrity, potentially due to shared genetic risk factors. Genetic correlation analyses were conducted in a large cohort of Mexican American families in San Antonio (N = 761, 58% females, ages 18–81 years; 41.3 ± 14.5) from the Genetics of Brain Structure and Function Study. Shared genetic variance was calculated between measures of adiposity [(body mass index (BMI; kg/m2) and waist circumference (WC; in)] and whole-brain and regional measurements of cerebral white matter integrity (fractional anisotropy). Whole-brain average and regional fractional anisotropy values for 10 major …

A Retrospective Survey Of Human Birth Defects As Recorded At Mcallen General Hospital In Mcallen, Texas, 1962-1972, Deana Brown

Theses and Dissertations - UTB/UTPA

Consecutive medical records of 10,622 births were viewed, January, 1962, through December, 1972, from McAllen General Hospital, McAllen, Texas. The overall incidence of birth defects was consistent with rates for the United States. Birth defects detected in Spanish surnamed were significantly higher than for non-Spanish surnamed. Spanish surnamed bore eight times more defects of the central nervous system than non Spanish surnamed. Males had significantly more defects than females, and had almost seven times more defects of the urogenital system. The most distinctive feature of this survey was the high incidence of atelectasis. Of all defective liveborn, over half had …