National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Chromosome 3p duplication

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My 9 month old son was recently diagnosed with trisomy 3p. I am having a hard time finding any information about the disorder. Any information you can share or direct me to would be most appreciated.

The following information may help to address your question:


What is chromosome 3p duplication?

Chromosome 3p duplication is a chromosome abnormality that occurs when there is an extra copy of genetic material on the short arm (p) of chromosome 3. The severity of the condition and the signs and symptoms depend on the size and location of the duplication and which genes are involved. Features that often occur in people with chromosome 3p duplication include developmental delay, intellectual disability, behavioral problems and distinctive facial features. Chromosome 3p duplication can be de novo or inherited from a parent with a balanced translocation.[1][2] Treatment is based on the signs and symptoms present in each person.
Last updated: 5/18/2015

What are the signs and symptoms of chromosome 3p duplication?

The signs and symptoms of chromosome 3p duplication vary but may include:[1][2]
  • Developmental delay
  • Intellectual disability
  • Hypotonia (poor muscle tone)
  • Cleft lip and palate
  • Behavioral problems
  • Short stature
  • Microcephaly (unusually small head)
  • Gastrointestinal abnormalities
  • Seizures
  • Congenital heart defects
  • Distinctive facial features (i.e. wide-spaced eyes, full cheeks, depressed nasal bridge, etc)
  • Genital abnormalities
Last updated: 5/18/2015

What causes chromosome 3p duplication?

People with chromosome 3p duplication have an extra (duplicate) copy of the genetic material located on the short arm (p) of chromosome 3 in each cell. The features associated with the condition vary significantly from person to person depending on the size and location of the duplication and which genes are involved.[1][2]

In some cases, this duplication is inherited from a parent with a balanced translocation. Other cases are considered "de novo" and occur sporadically as a random event when the egg or the sperm is made. There is nothing that a person can do to cause or prevent this duplication from happening.[1][2]
Last updated: 5/19/2015

Is chromosome 3p duplication inherited?

Chromosome 3p duplication can be de novo or inherited from a parent with a balanced translocation.[1][2]

"De novo" duplications occur sporadically as a random event during the formation of the egg or sperm. In these cases, a person would have no family history of the condition but could pass the duplication on to children.

Other cases of chromosome 3p duplication are the result of a balanced translocation in one of the parents. Carriers of a balanced translocation generally do not have any unusual symptoms or health problems; however, they have an increased risk of having children with a chromosome abnormality. To read more about balanced translocations, click here.
Last updated: 5/19/2015

How can I find a genetics professional in my area?

To find a medical professional who specializes in genetics, you can ask your doctor for a referral or you can search for one yourself. Online directories are provided by the American College of Medical Genetics and the National Society of Genetic Counselors. If you need additional help, contact a GARD Information Specialist. You can also learn more about genetic consultations from Genetics Home Reference.
Last updated: 12/6/2017

We hope this information is helpful. We strongly recommend you discuss this information with your doctor. If you still have questions, please contact us.

Warm regards,
GARD Information Specialist

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  1. Han DH, Chang JY, Lee WI, Bae CW. A case of partial trisomy 3p syndrome with rare clinical manifestations. Korean J Pediatr. March 2012; 55(3):107-110.
  2. Natera-de Benito D, García-Pérez MA, Martínez-Granero MÁ, Izquierdo-López L.. A patient with a duplication of chromosome 3p (p24.1p26.2): a comparison with other partial 3p trisomies. Am J Med Genet A. 2014 Feb;164A(2):548-50. February 2014; 164A(2):548-550.