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Genetic and Rare Diseases Information Center (GARD)

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Chromosome 3p duplication

Other Names for this Disease
  • 3p duplication
  • 3p trisomy
  • Duplication 3p
  • Partial trisomy 3p
  • Trisomy 3p
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How is chromosome 3, trisomy 3p inherited?

Trisomy 3p can happen on its own as a new chromosome abnormality (referred to as de novo) in offspring, or it can be caused by a parent having a balanced translocation. In most cases, an individual who has trisomy 3p is the child of a parent who is a balanced translocation carrier.[1] People generally have 23 pairs of chromosomes and inherit one in each pair from each parent. Sometimes, a section from one chromosome of a particular pair changes places with a section from a chromosome of another pair. When the two breaks do not pass through a gene and there is no gain or loss of material it is called a balanced translocation. Someone with a balanced translocation (a carrier) usually has no health or developmental problems, although they may sometimes have difficulties when they want to have children. Balanced translocations happen naturally. They can be new (de novo) or they can be passed down in families from parent to child through the generations. New translocations occur when sperm or egg cells are forming or just after fertilization during the copying of the early cells that will become an embryo.[2] To read more about balanced translocations, click here.

Even though the chromosome rearrangement is balanced in a parent, it can result in an unbalanced rearrangement in a child. The child can receive too little, or an extra amount, of the chromosome material that is rearranged in the parent. Trisomy 3p often results from the child receiving an extra copy of some or all of the material on the short arm of chromosome 3. The chance that carrying a balanced translocation will cause a child to receive unbalanced chromosomal material varies from less than 1% to up to 20% according to the specific chromosomes involved in the translocation.[3]
Last updated: 6/10/2011

  1. Joel Charrow, Maimon M. Cohen, and Diana Meeker. Duplication 3p Syndrome: Report of a New Case and Review of the Literature. American Journal of Medical Genetics. 1981; 8:431-436.
  2. Balanced translocations. Unique. 2009; Accessed 2/1/2011.
  3. Kristine Barlow-Stewart. Changes to Chromosome Structure - Translocations. Centre for Genetics Education. June 2007; Accessed 2/1/2011.