RT Journal Article SR Electronic T1 Partial trisomy 12 in a mentally retarded boy and translocation (12;21) in his mother JF Journal of Medical Genetics JO J Med Genet FD BMJ Publishing Group Ltd SP 299 OP 303 DO 10.1136/jmg.11.3.299 VO 11 IS 3 A1 Hobolth, N. A1 Jacobsen, Petrea A1 Mikkelsen, Margareta YR 1974 UL http://jmg.bmj.com/content/11/3/299.abstract AB Cytogenetic studies of an infant with malformations and a peculiar appearance showed a partial trisomy of chromosome 12. The mother carried a translocation of the distal part of chromosome 12 onto the short arm of chromosome 21, with breakpoints most likely at 12q24 and 21p11.