HLA-DR4 as a risk allele for autism acting in mothers of probands possibly during pregnancy.

Objectives: To test whether HLA-DR4 acts in the mother, possibly during pregnancy, to contribute to the phenotype of autistic disorder in her fetus.

Design: Transmission disequilibrium testing in case mothers and maternal grandparents.

Setting: Previous studies have consistently shown increased frequency of HLA-DR4 in probands with autism and their mothers, but not their fathers.

Analysis of case-parent trios at a locus with a deletion allele: association of GSTM1 with autism.

Background: Certain loci on the human genome, such as glutathione S-transferase M1 (GSTM1), do not permit heterozygotes to be reliably determined by commonly used methods. Association of such a locus with a disease is therefore generally tested with a case-control design. When subjects have already been ascertained in a case-parent design however, the question arises as to whether the data can still be used to test disease association at such a locus.