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Disease Profile

Trisomy 13

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

1-9 / 1 000 000

US Estimated

Europe Estimated

Age of onset



Q91.4 Q91.5 Q91.6 Q91.7


Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Patau syndrome; Chromosome 13, trisomy 13 complete; Complete trisomy 13 syndrome;


Chromosome Disorders; Congenital and Genetic Diseases; Digestive Diseases;


Trisomy 13 is a type of chromosome disorder characterized by having 3 copies of chromosome 13 in cells of the body, instead of the usual 2 copies. In some people, only a portion of cells contains the extra chromosome 13 (called mosaic trisomy 13), whereas other cells contain the normal chromosome pair.[1][2][3] Trisomy 13 causes severe intellectual disability and many physical abnormalities, such as congenital heart defects; brain or spinal cord abnormalities; very small or poorly developed eyes (microphthalmia); extra fingers or toes; cleft lip with or without cleft palate; and weak muscle tone (hypotonia). Most cases are not inherited and result from a random error during the formation of eggs or sperm in healthy parents.[2] Trisomy 13 is diagnosed based on the symptoms, clinical exam, and confirmed by the results of a chromosome test. Due to various life-threatening medical problems, many infants with trisomy 13 do not survive past the first days or weeks of life.[2]


Trisomy 13 is associated with severe intellectual disability and physical abnormalities in many parts of the body. People with this condition often have congenital heart defects, brain or spinal cord abnormalities, very small or poorly developed eyes (microphthalmia), extra fingers and/or toes (polydactyly), cleft lip or palate, and decreased muscle tone (hypotonia).[2] Many infants with trisomy 13 fail to grow and gain weight at the expected rate (failure to thrive); have severe feeding difficulties; and may stop breathing for short periods of time (apnea).[1]

Other features of trisomy 13 may include:[3]

Trisomy 13 involves multiple abnormalities, many of which are life-threatening. More than 80% of children with trisomy 13 do not survive past the first month of life. For those that do survive, complications may include:[3]

  • Breathing difficulty or lack of breathing (apnea)
  • Deafness
  • Feeding problems
  • Heart failure
  • Vision problems

People with trisomy 13 who survive infancy have severe intellectual disability and developmental delays, and are at increased risk for cancers.[4]

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
80%-99% of people have these symptoms
Abnormality of pelvic girdle bone morphology
Abnormal shape of pelvic girdle bone
Abnormality of the fontanelles or cranial sutures
Absence of eyeballs
Failure of development of eyeball
Missing eyeball
No eyeball

[ more ]

Atrial septal defect
An opening in the wall separating the top two chambers of the heart
Hole in heart wall separating two upper heart chambers

[ more ]

Bilateral single transverse palmar creases
Cleft palate
Cleft roof of mouth
Cognitive impairment
Abnormality of cognition
Cognitive abnormality
Cognitive defects
Cognitive deficits
Intellectual impairment
Mental impairment

[ more ]

Cystic hygroma
Hydrops fetalis
Abnormally close eyes
Closely spaced eyes

[ more ]

Intellectual disability, severe
Early and severe mental retardation
Mental retardation, severe
Severe mental retardation

[ more ]

Intrauterine growth retardation
Prenatal growth deficiency
Prenatal growth retardation

[ more ]

Low-set ears
Low set ears
Lowset ears

[ more ]

Malar flattening
Zygomatic flattening
Median cleft lip
Central cleft upper lip
Abnormally small eyeball
Muscular hypotonia
Low or weak muscle tone
Neurological speech impairment
Speech disorder
Speech impairment
Speech impediment

[ more ]

Patent ductus arteriosus
Postaxial hand polydactyly
Extra little finger
Extra pinkie finger
Extra pinky finger

[ more ]

Severe global developmental delay
Ventricular septal defect
Hole in heart wall separating two lower heart chambers
30%-79% of people have these symptoms
Abnormal eyelash morphology
Abnormal eyelashes
Abnormality of the eyelashes
Eyelash abnormality

[ more ]

Abnormal lung lobation
Abnormal morphology of female internal genitalia
Abnormal retinal vascular morphology
Abnormality of retina blood vessels
Abnormality of the antihelix
Abnormality of the dentition
Abnormal dentition
Abnormal teeth
Dental abnormality

[ more ]

Abnormality of the helix
Abnormality of the middle ear
Abnormality of the ribs
Rib abnormalities
Abnormality of the ureter
Abnormality of vision
Abnormality of sight
Vision issue

[ more ]

Aplasia/Hypoplasia of the iris
Absent/small iris
Absent/underdeveloped iris

[ more ]

Arnold-Chiari malformation
Calvarial skull defect
Cranial defect
Skull defect

[ more ]

Capillary hemangioma
Strawberry birthmark
Clouding of the lens of the eye
Cloudy lens

[ more ]

Undescended testes
Undescended testis

[ more ]

Deeply set eye
Deep set eye
Deep-set eyes
Sunken eye

[ more ]

Displacement of the urethral meatus
Cleft hand
Lobster claw hand

[ more ]

High, narrow palate
Narrow, high-arched roof of mouth
Narrow, highly arched roof of mouth

[ more ]

Iris coloboma
Cat eye
Hunched back
Round back

[ more ]

Long philtrum
Multiple renal cysts
Multiple kidney cysts
Narrow chest
Low chest circumference
Narrow shoulders

[ more


Most cases of trisomy 13 are caused by random events during the formation of eggs or sperm in healthy parents (prior to conception). Trisomy 13 is typically due to having three full copies of chromosome 13 in each cell in the body, instead of the usual two copies. This is referred to as complete trisomy 13 or full trisomy 13. The extra genetic material disrupts the normal course of development, causing the characteristic features seen in trisomy 13.

Trisomy 13 can also occur when part of chromosome 13 becomes attached (translocated) to another chromosome during the formation of eggs or sperm, or very early in fetal development. This is referred to as translocation trisomy 13. This type of trisomy 13 occurs when someone has two normal copies of chromosome 13, plus an extra copy of chromosome 13 that is attached to another chromosome. Translocation trisomy 13 can be inherited. Approximately 20% of cases of trisomy 13 are caused by a translocation. 

In rare cases, only part of chromosome 13 is present in three copies in each cell (rather than the full chromosome); this is called partial trisomy 13. In other rare cases, a person has an extra copy of chromosome 13 in only some of the body's cells; this is called mosaic trisomy 13. The severity of mosaic trisomy 13 depends on the type and proportion of cells that have the extra chromosome.[5][6]


Diagnosis of trisomy 13 is based on the symptoms, a clinical exam, and is confirmed by the results of a genetic test to look at the chromosomes known as a karyotype.

While most cases of trisomy 13 occur by chance, a few cases are due to the presence of a translocation involving chromosome 13 in a parent. Parents who are at risk to have a translocation due to their family history can have a blood test called a karyotype, which can determine if a translocation is present.

Prenatal testing or screening (such as maternal blood screening, non-invasive prenatal screeningfetal ultrasound, chorionic villus sampling, or amniocentesis) is also available to determine if a current pregnancy is at risk for, or is affected by, trisomy 13 or other chromosome disorders.

People with a family history of trisomy 13 who are interested in learning about genetic screening or testing for themselves or family members are encouraged speak with a genetic counselor or other genetics professional.


Treatment for trisomy 13 is focused on managing the symptoms, and providing comfort and supportive care.[3] Surgeries are generally withheld for the first few months of life because of the high mortality rate associated with trisomy 13. Parents and medical personnel must carefully weigh decisions about extraordinary life-prolonging measures against the severity of the neurological and physical defects that are present and the likelihood of post-surgical recovery or prolonged survival.[4]


Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

    Learn more

    These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

    Where to Start

    • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
    • Genetics Home Reference (GHR) contains information on Trisomy 13. This website is maintained by the National Library of Medicine.
    • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

      In-Depth Information

      • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
      • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
      • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
      • PubMed is a searchable database of medical literature and lists journal articles that discuss Trisomy 13. Click on the link to view a sample search on this topic.


        1. Trisomy 13 Syndrome. National Organization for Rare Disorders (NORD). 2007; https://rarediseases.org/rare-diseases/trisomy-13-syndrome/.
        2. Trisomy 13. Genetics Home Reference (GHR). November 2013; https://ghr.nlm.nih.gov/condition/trisomy-13.
        3. Haldeman-Englert C. Trisomy 13. MedlinePlus. September 2013; https://www.nlm.nih.gov/medlineplus/ency/article/001660.htm.
        4. Best RG, Stallworth J. Patau Syndrome. eMedicine. 2007; https://emedicine.medscape.com/article/947706-overview. Accessed 10/13/2009.
        5. Trisomy 13. Genetics Home Reference. November 2013; https://ghr.nlm.nih.gov/condition/trisomy-13.
        6. Robert L. Nussbaum, Roderick R. McInnes, Huntington F. Willard. Thompson & Thompson Genetics In Medicine. Philadelphia, PA: Saunders Elsevier; 2007; 7:75-95.
        7. Trisomy 13 Syndrome. National Organization for Rare Disorders (NORD). 2007; https://rarediseases.org/rare-diseases/trisomy-13-syndrome/.

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