Dr. Langefeld is a statistical geneticist whose research focuses on the mapping of complex genetic traits. Such traits are familial, but their inheritance patterns appear to differ from simple Mendelian inheritance due to incomplete penetrance, sporadic cases, genetic heterogeneity, epistasis and gene-environment interactions. Thus, the magnitude of the genetic effect may be modest or masked by the complexity of the etiologic mechanism. The ultimate goal of this research is to assist in the isolation and cloning of disease-predisposing genes for the prevention and treatment of the disease.

Dr. Langefeld’s methodological research focuses on the development of association and linkage methods for the mapping of complex genetic traits. He has developed a class of regression-based tests for linkage asymptotically equivalent to the class of nonparametric linkage (NPL) tests developed by Whittemore and Halpern (1994; Langefeld and Boehnke 1999, Langefeld et al., In Press). The primary advantage of NPL regression is that it allows one to simultaneously evaluate the effects of multiple loci, their interactions and their interactions with environmental factors or other phenotypic characteristics. In collaboration with Cralen Davis, he has developed an extension of regression diagnostic methods that can assist in the identification of pedigrees who disproportionately contribute evidence for linkage at a particular locus or loci, or for whom a proposed model does not fit (Davis et al., In Press). In collaboration with Dr. Michael Boehnke (University of Michigan) and Dr. Linda Green (Wake Forest University, Department of Public Health Sciences),he has developed a test for linkage disequilibrium, the discordant alleles test (DAT), for when parental data are not available (Boehnke and Langefeld (1998). In addition to statistical genetics, he maintains a broad interest in biostatistics and, in particular, longitudinal data analysis and model validation (Miller et al., 1993, 1996). Dr. Langefeld was a finalist for the 2000 James V.Neel Young Investigator Award of the International Society of Genetic Epidemiology.

Dr. Langefeld has a strong interest in diabetes (type 1, type 2 andgestational) and its complications. He is a co-investigator onNIH-funded grants for type 2 diabetes (IRAS Family Study: Geneticsof Insulin Resistance, Mapping Genes for NIDDM Nephropathy inAfrican Americans) and systemic lupus erythematosus SpecializedCenter of Research (SCOR) in Systemic Lupus, Gene Mapping inSystemic Lupus Erythematosus), end-stage renal disease (Genetic Analysis of Human Hypertensive ESRD) and asthma (CollaborateStudies on the Genetics of Asthma). Dr. Langefeld is also involved inthe Finland-United States Investigation of Non- Insulin-DependentDiabetes Mellitus (FUSION) Study.