J Med Genet 24:93-96 doi:10.1136/jmg.24.2.93
  • Research Article

New assignment of the adenosine deaminase gene locus to chromosome 20q13 X 11 by study of a patient with interstitial deletion 20q.


A karyotype 46,XY,del(20)(q11 X 23q13 X 11) was found in a three year old boy with mental and growth retardation, low set ears, broad nasal bridge, and macrostomia. Adenosine deaminase (ADA) activity was reduced by about 50%, assigning the gene locus to the deleted segment. A review of the previously reported regional assignments suggests that the ADA gene is in the region of band 20q13 X 11.