The study of ABO blood groups and Down's syndrome.
D000017:ABO Blood-Group System; D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002904:Chromosomes, Human, 21-22 and Y; D003582:Cytogenetics; D004314:Down Syndrome / Q000097:blood*; D005787:Gene Frequency; D006801:Humans; D007223:Infant; D007621:Karyotyping; D010375:Pedigree; D014314:Trisomy
D000017:ABO Blood-Group System