Children's Health and Wellness

Translocations

What are translocations?

The term translocation is used when the location of specific chromosome material changes. There are two main types of translocations: reciprocal and Robertsonian. In a reciprocal translocation, two different chromosomes have exchanged segments with each other:

Genetic illustration demonstrating reciprocal translocation
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In a Robertsonian translocation, an entire chromosome attaches to another at the centromere. The centromere is the center part of a chromosome that appears "pinched" between the p and q arms:

Genetic illustration demonstrating Robertsonian translocation
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This newly formed chromosome is called the translocation chromosome. The translocation in this example is between chromosomes #14 and 21. When a baby is born with this type of translocation chromosome (between #14 and 21), in addition to one normal 14 and two normal 21 chromosomes, the baby will have Down syndrome. This is also called translocation Down syndrome.

Online Source: Can Changes in the Structure of Chromosomes Affect Health and Development?, U.S. National Library of Medicine Genetics Home Reference http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/structuralchanges
Online Source: Learning About Down Syndrome, National Human Genome Research Institutehttp://www.genome.gov/19517824
Online Editor: Geller, Arlene
Online Medical Reviewer: Clark, Heather, MS, CGC
Online Medical Reviewer: newMentor board-certified, academically affiliated clinician
Date Last Reviewed: 6/23/2013
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