title: Comparison of high-resolution human leukocyte antigen haplotype frequencies in different ethnic groups: Consequences of sampling fluctuation and haplotype frequency distribution tail truncation.
abstract: High-resolution haplotype frequency estimations and descriptive metrics are becoming increasingly popular for accurately describing human leukocyte antigen diversity. In this study, we compared sample sets of publically available haplotype frequencies from different populations to characterize the consequences of unequal sample size on haplotype frequency estimation. We found that for low samples sizes (a few thousand), haplotype frequencies were overestimated, affecting all descriptive metrics of the underlying distribution, such as most frequent haplotype, the number of haplotypes, and the mean/median frequency. This overestimation was a result of random sample fluctuation and truncation of the tail end of the frequency distribution that comprises the least frequent haplotypes. Finally, we simulated balanced datasets through resampling and contrasted the disparities of descriptive metrics among equal and unequal datasets. This simulation resulted in the global description of the most frequent human leukocyte antigen haplotypes worldwide.
authors: Children's Hospital Research Institute, Oakland, CA 94609, USA.
authors: Derek James
authors: DJ
authors: Pappas
authors: University of California, Berkeley, Berkeley, CA, USA.
authors: Alannah
authors: A
authors: Tomich
authors: Registre France Greffe de Moelle, Agence de la Biomédecine, Paris, France.
authors: Federico
authors: F
authors: Garnier
authors: Registre France Greffe de Moelle, Agence de la Biomédecine, Paris, France.
authors: Evelyne
authors: E
authors: Marry
authors: Registre France Greffe de Moelle, Agence de la Biomédecine, Paris, France; University of California, San Francisco, San Francisco, CA, USA. Electronic address: pierreantoine.gourraud@ucsf.edu.
authors: Pierre-Antoine
authors: PA
authors: Gourraud
mesh_terms: D066264:Datasets as Topic; D005006:Ethnicity; D005787:Gene Frequency; D006680:HLA Antigens / Q000235:genetics*; D006239:Haplotypes; D006801:Humans; D011110:Polymorphism, Genetic; D012042:Registries; D012044:Regression Analysis; D018401:Sample Size; D015983:Selection Bias; D014019:Tissue Donors
chemical_list: D006680:HLA Antigens
keywords: Bone marrow donor registry; Genetic epidemiology; Haplotype; Immunogenetic; Population