Partial trisomy 20 confirmed by gene dosage studies

Am J Med Genet. 1979;4(4):357-64. doi: 10.1002/ajmg.1320040407.


We describe a female infant with multiple congenital anomalies and mental retardation, pre- and postnatal growth failure, microcephaly, unusual facial appearance, and minor skeletal anomalies, all very suggestive of the partial trisomy 20(p) syndrome. Although she was born to karyotypically normal parents, she had an extra small metacentric chromosome. Analysis of metaphase and prometaphase chromosomes by GTG banding and Giemsa 11 staining showed that the extra chromosome was a number 20 with a deletion of the distal end of the long arm. Gene dose studies of adenosine deaminase (ADA) and inosine triphosphatase (ITP) supported the cytogenetic interpretation.

Publication types

  • Case Reports
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Abnormalities, Multiple / genetics
  • Adenosine Deaminase / genetics
  • Chromosome Banding
  • Chromosome Mapping
  • Chromosomes, Human, 19-20*
  • Female
  • Genes*
  • Genetic Markers
  • Humans
  • Infant, Newborn
  • Inosine Triphosphate / genetics
  • Intellectual Disability / genetics
  • Psychomotor Disorders / genetics
  • Pyrophosphatases / genetics
  • Trisomy*


  • Genetic Markers
  • Inosine Triphosphate
  • Adenosine Deaminase
  • Pyrophosphatases
  • inosine triphosphatase