title: HLA haplotypes in Singapore: a study of mothers and their cord blood units.
abstract: During 2005, a total of 174 cord blood units with their paired maternal samples from the Singapore Cord Blood Bank were typed for HLA-A, -B, -C at intermediate resolution and DRB1 at allelic resolution. Analysis of allele segregation in mother and child assigned 185 different four locus (HLA-A, -B, -C, -DRB1) haplotypes in Chinese, 66 in Malays, and 34 in Asian Indians. Very few four locus haplotypes were shared among population groups. To evaluate the frequencies of four locus haplotypes, the Expectation Maximization algorithm was used with HLA assignments from 536 unrelated Chinese volunteers from the Singapore Bone Marrow Donor Program registry. The paired maternal and cord blood study identified 75 different B-C associations in Chinese, 52 in Malays, and 24 in Asian Indians. Common B-C associations may be shared among population groups; for example, B*4001g-Cw*0702g was common in Chinese and Malays, whereas B*1502g-Cw*0801g and B*3501g-Cw*0401g were found in all three groups. The high diversity of four locus haplotypes originates from multiple combinations of both HLA-A and -DRB1 alleles with each B-C haplotype.
authors.affiliation: Department of Pediatrics, Georgetown University, Washington, DC, USA.
authors.forename: Ting F
authors.initials: TF
authors.lastname: Tang
authors.forename: Lihua
authors.initials: L
authors.lastname: Hou
authors.forename: Minghua
authors.initials: M
authors.lastname: Chen
authors.forename: Ian
authors.initials: I
authors.lastname: Belle
authors.forename: Steven
authors.initials: S
authors.lastname: Mack
authors.forename: Alex
authors.initials: A
authors.lastname: Lancaster
authors.forename: Grace Y H
authors.initials: GY
authors.lastname: Ho
authors.forename: William Y K
authors.initials: WY
authors.lastname: Hwang
authors.forename: Fidah
authors.initials: F
authors.lastname: Alsagoff
authors.forename: Jennifer
authors.initials: J
authors.lastname: Ng
authors.forename: Carolyn Katovich
authors.initials: CK
authors.lastname: Hurley
mesh_terms: D044466:Asian People / Q000235:genetics*; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D005787:Gene Frequency; D006680:HLA Antigens / Q000235:genetics*; D015234:HLA-A Antigens / Q000235:genetics; D015235:HLA-B Antigens / Q000235:genetics; D015236:HLA-C Antigens / Q000235:genetics; D006684:HLA-DR Antigens / Q000235:genetics; D059811:HLA-DRB1 Chains; D006239:Haplotypes; D006650:Histocompatibility Testing; D006801:Humans; D008297:Male; D009035:Mothers; D012846:Singapore; D044465:White People / Q000235:genetics*
chemical_list: D006680:HLA Antigens; D015234:HLA-A Antigens; D015235:HLA-B Antigens; D015236:HLA-C Antigens; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains