title: Confirmation of the association of the C4B null allelle in autism.
abstract: The objective of this study was to examine and attempt to confirm our previous findings of an increased frequency of the C4B null allele (C4BQ0) in subjects with autism. Newly identified subjects from Utah and Oregon were studied. Families evaluated included 85 who had a child with autism and 69 control families. Of the subjects with autism studied, 42.4% carried at least one C4BQ0, compared with 14.5% of the control subjects (p = 0.00013), with a relative risk of 4.33. Over half of the C4B null alleles in the subjects with autism involved C4A duplications. A marked increase in the ancestral haplotype 44.1 that lacks a C4B gene and has 2 C4A genes was also observed. The results of this study suggest that the human leukocyte antigen class III C4BQ0 significantly increases the risk for autism.
authors.affiliation: Center for Persons with Disabilities, Utah State University, Logan, UT 84322, USA. dennis@cpd2.usu.edu
authors.forename: Dennis
authors.initials: D
authors.lastname: Odell
authors.forename: Alma
authors.initials: A
authors.lastname: Maciulis
authors.forename: Adele
authors.initials: A
authors.lastname: Cutler
authors.forename: Louise
authors.initials: L
authors.lastname: Warren
authors.forename: William M
authors.initials: WM
authors.lastname: McMahon
authors.forename: Hilary
authors.initials: H
authors.lastname: Coon
authors.forename: Gene
authors.initials: G
authors.lastname: Stubbs
authors.forename: Kathy
authors.initials: K
authors.lastname: Henley
authors.forename: Anthony
authors.initials: A
authors.lastname: Torres
mesh_terms: D001321:Autistic Disorder / Q000235:genetics*; D015935:Complement C4b / Q000235:genetics*; D005787:Gene Frequency; D005838:Genotype; D006649:Histocompatibility Antigens / Q000235:genetics; D006801:Humans; D016133:Polymerase Chain Reaction
chemical_list: D006649:Histocompatibility Antigens; D015935:Complement C4b