Chromosome 5, Trisomy 5p

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report Chromosome 5, Trisomy 5p is not the name you expected.

Disorder Subdivisions

  • None

General Discussion

Trisomy 5p is a rare chromosomal disorder in which all or a portion of the short arm (p) of chromosome 5 (5p) appears three times (trisomy) rather than twice in cells of the body. Often the duplicated portion of 5p (trisomy) is due to a complex rearrangement involving other chromosomes. These individuals have a variable phenotype depending on which chromosome is involved, the size of the duplication and whether there is loss of material from the same or another chromosome. There are rare cases with an isolated duplication of 5p. These individuals have less variability. The variability that does appear is due to the size and location of the duplication. The individuals with only the duplication allow a better description of the symptoms (phenotype) and definition of a critical region for certain symptoms (cardiac abnormalities and seizures). Many affected infants and children have abnormalities that include low muscle tone (hypotonia); an unusually large head (macrocephaly) and additional abnormalities of the head and facial (craniofacial) area; long, slender fingers (arachnodactyly); delays in the acquisition of skills requiring the coordination of mental and physical activities (psychomotor retardation); and intellectual disability. Some affected individuals may have heart defects and seizures. Not all individuals with trisomy 5p will have all of the symptoms of the disorder.

Supporting Organizations

Chromosome Disorder Outreach, Inc.

P.O. Box 724
Boca Raton, FL 33429-0724
Tel: (561)395-4252
Fax: (561)395-4252

Genetic and Rare Diseases (GARD) Information Center

PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311

March of Dimes

1275 Mamaroneck Avenue
White Plains, NY 10605
Tel: (914)997-4488
Fax: (914)997-4763
Email: or
Website: and

Support Organization for Trisomy 13/18 and Related Disorders, UK

c/o Christine Rose
48 Froggatts Ride
West Midlands, B76 2TQ SOFT
United Kingdom
Tel: 1213513122

Support Organization for Trisomy 18, 13, and Related Disorders

2982 S. Union Street
Rochester, NY 14624-1926
Fax: (585)594-1957
Tel: (800)716-7638

The Arc

1825 K Street NW, Suite 1200
Washington, DC 20006
Tel: (202)534-3700
Fax: (202)534-3731
Tel: (800)433-5255

UNIQUE - Rare Chromosome Disorder Support Group

G1 The Stables
Station Road West
Oxted, RH8 9EE
United Kingdom
Tel: 0044 (0)1883 723356

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). For a full-text version of this report, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report.

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

Last Updated:  3/19/2013
Copyright  2013 National Organization for Rare Disorders, Inc.