Neonatal respiratory distress syndrome (RDS) is the most common respiratory cause of mortality and morbidity among infants in the United States. While RDS is most commonly attributed to a developmental immaturity of pulmonary surfactant production, a genetic mechanism is suggested by studies of twins, ethnicity, gender, and lethal mutations in surfactant-related genes (SFTPB, SFTPC, and ABCA3). Prior research to define the genetic mechanisms underlying neonatal RDS has focused on common genetic variants within single candidate genes and explains only a small proportion of disease heritability. Research in complex adult diseases that reduce reproductive fitness suggests that combinations of rare, highly penetrant variants in multiple genes account for disease heritability. Our laboratory has identified statistical and functional associations of rare variants in surfactant-related genes with neonatal RDS. The goals of this proposal are to identify gene loci with excess, rare, functional variants that statistically account for the missing heritability of RDS and to develop methods to test the biologic mechanisms by which genetic variants disrupt surfactant metabolism. First, we will use next generation sequencing to determine the population-based frequencies of rare genetic variants among five surfactant-related genes (SFTPC, ABCA3, LPCAT, CHPT, and PCYT1B) using 1,116 infant samples obtained from the Missouri Department of Health. Second, we will determine whether excess, rare, functionally disruptive variants in these five genes are overrepresented among infants with RDS compared to infants without RDS in already available DNA samples with informed consent (N=940 infants of African and European descent). Third, we will use cell-based functional assays to investigate the underlying biologic mechanisms of these disruptive variants. This comprehensive research strategy is novel because we will study candidate genes with higher resolution, use software based algorithms to assess variant functionality, use traditional (regression) and novel (Collapsing Methods, BimBam, logic regression) statistical approaches to evaluate variant interactions, and use cell-based assays to study the functionality of identified variants and combinations of variants. The development of cell-based assays will permit mechanistic study of variants identified through statistical associations and provide the basis for the long-term development of diagnostic and therapeutic approaches for affected infants. The combination of my clinical experience, prior didactic and mentored training in genetic epidemiology, and an integrated training plan that allows me to develop skills in the use of surrogate cell systems will enable me to develop into an independent investigator that can bridge statistical observation with functional mechanism and translate these findings into specific therapeutic approaches for infants with RDS.

Public Health Relevance

Respiratory distress syndrome (RDS) is the most frequent respiratory cause of death and morbidity in infants less than 1 year of age in the United States;studies of ethnic groups, gender, and clinical reports of single gene causes of lethal neonatal RDS strongly suggest that genetic mechanisms contribute to the risk for RDS. This proposal will discover statistical and functional associations and interactions between/among five pulmonary surfactant-related genes with risk for neonatal RDS. Understanding the genetic mechanisms that underlie RDS is critical for improving outcomes of children in the United States and reducing the costs of their health care.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Clinical Investigator Award (CIA) (K08)
Project #
5K08HL105891-02
Application #
8293039
Study Section
Special Emphasis Panel (ZHL1-CSR-K (M4))
Program Officer
Colombini-Hatch, Sandra
Project Start
2011-07-01
Project End
2015-06-30
Budget Start
2012-07-01
Budget End
2013-06-30
Support Year
2
Fiscal Year
2012
Total Cost
$125,528
Indirect Cost
$9,298
Name
Washington University
Department
Pediatrics
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Towe, Christopher T; White, Frances V; Grady, R Mark et al. (2018) Infants with Atypical Presentations of Alveolar Capillary Dysplasia with Misalignment of the Pulmonary Veins Who Underwent Bilateral Lung Transplantation. J Pediatr 194:158-164.e1
Wambach, Jennifer A; Wegner, Daniel J; Yang, Ping et al. (2018) Functional characterization of biallelic RTTN variants identified in an infant with microcephaly, simplified gyral pattern, pontocerebellar hypoplasia, and seizures. Pediatr Res 84:435-441
Wambach, Jennifer A; Stettner, Georg M; Haack, Tobias B et al. (2017) Survival among children with ""Lethal"" congenital contracture syndrome 11 caused by novel mutations in the gliomedin gene (GLDN). Hum Mutat 38:1477-1484
Eldridge, Whitney B; Zhang, Qunyuan; Faro, Albert et al. (2017) Outcomes of Lung Transplantation for Infants and Children with Genetic Disorders of Surfactant Metabolism. J Pediatr 184:157-164.e2
Chen, Yu-Jun; Wambach, Jennifer Anne; DePass, Kelcey et al. (2016) Population-based frequency of surfactant dysfunction mutations in a native Chinese cohort. World J Pediatr 12:190-5
Wambach, Jennifer A; Yang, Ping; Wegner, Daniel J et al. (2016) Functional Characterization of ATP-Binding Cassette Transporter A3 Mutations from Infants with Respiratory Distress Syndrome. Am J Respir Cell Mol Biol 55:716-721
Shen, Carol L; Zhang, Qunyuan; Meyer Hudson, Julia et al. (2016) Genetic Factors Contribute to Risk for Neonatal Respiratory Distress Syndrome among Moderately Preterm, Late Preterm, and Term Infants. J Pediatr 172:69-74.e2
Jackson, T; Wegner, D J; White, F V et al. (2015) Respiratory failure in a term infant with cis and trans mutations in ABCA3. J Perinatol 35:231-2
Szafranski, Przemyslaw; Dharmadhikari, Avinash V; Wambach, Jennifer A et al. (2014) Two deletions overlapping a distant FOXF1 enhancer unravel the role of lncRNA LINC01081 in etiology of alveolar capillary dysplasia with misalignment of pulmonary veins. Am J Med Genet A 164A:2013-9
Wambach, Jennifer A; Wegner, Daniel J; Heins, Hillary B et al. (2014) Synonymous ABCA3 variants do not increase risk for neonatal respiratory distress syndrome. J Pediatr 164:1316-21.e3

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