title: Monozygotic twins with ring chromosome 22.
mesh_terms: D002675:Child, Preschool; D002869:Chromosome Aberrations; D002904:Chromosomes, Human, 21-22 and Y; D004200:Diseases in Twins; D005260:Female; D006801:Humans; D006948:Hyperkinesis / Q000235:genetics; D008607:Intellectual Disability / Q000235:genetics*; D007621:Karyotyping