title: Congenital tetragametic blood chimerism explains a case of questionable paternity.
abstract: Human chimerism is the presence of ≥ 2 cell populations in one person that contain genetic material from more than one zygote. Chimerism may be either acquired by transfusion or transplantation of donor cells, or congenital arising from embryo fusion or dizygotic twin-twin transfusion. We encountered a 4-year-old boy with developmental hip dysplasia whose preoperative (serologic) blood group was AB, but whose red cell agglutination was atypical ("mixed field") and caused us to study the patient's parents' ABO blood groups. Parental blood groups (AB and O) suggested possible nonparentage. An alternative explanation of the findings was that the child was chimeric or mosaic. Molecular cloning and genotyping of his ABO locus in leukocytes revealed two heterozygous genotypes: A102/O01 and B101/O01. Other loci, each of which possessed three distinct alleles, unambiguously showed transmission of two alleles from either the child's mother (e.g., HLA-A) or two alleles from the child's father (e.g., D8S1179). Findings indicate that the child is a tetragametic chimera.
authors.affiliation: Shenzhen Institute of Transfusion Medicine, Shenzhen Blood Center, Nigang Xi Road, Meigang Nan Street, Shenzhen 518035, Guangdong, China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Yu
authors.forename: Qian
authors.initials: Q
authors.lastname: Li
authors.forename: Suqing
authors.initials: S
authors.lastname: Gao
authors.forename: Yuqing
authors.initials: Y
authors.lastname: Su
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Deng
mesh_terms: D000017:ABO Blood-Group System / Q000235:genetics; D001788:Blood Grouping and Crossmatching; D002675:Child, Preschool; D046528:Chimerism; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics; D010334:Paternity; D016133:Polymerase Chain Reaction; D017421:Sequence Analysis
chemical_list: D000017:ABO Blood-Group System