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Disease Profile

17q12 duplication

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.


US Estimated

Europe Estimated

Age of onset





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)

Chromosome 17q12 duplication syndrome; 17q12 microduplication syndrome; Trisomy 17q12;


Congenital and Genetic Diseases


17q12 duplication occurs when a person has an extra copy of a portion of chromosome 17. Our genetic information is organized in structures called chromosomes. People with 17q12 duplication have an extra piece of genetic information from chromosome 17. Some people with this duplication do not have any signs or symptoms. Other people may have symptoms including intellectual disability, developmental delay, and behavioral challenges.[1] Some people with 17q12 duplication may also have vision problems. Rarely, people with 17q12 duplication may also have other health problems, such as problems with the heart or kidneys.[2]

17q12 duplication occurs when a portion of chromosome 17 is duplicated. When the duplication is inherited from a parent, it is inherited in an autosomal dominant manner. The duplication may be suspected if a doctor sees signs and symptoms such as developmental delay, behavioral problems, and intellectual disability. Genetic testing using chromosomal microarray (CMA) may confirm the diagnosis. Treatment options may include physical, occupational, and speech therapies, as well as management by a psychiatrist or psychologist to assist with any behavioral challenges.[2]


The signs and symptoms of 17q12 duplication most commonly include intellectual disability and developmental delay. Intellectual disability may be mild to severe. Developmental delay means that some children may not reach milestones such as sitting, standing, or walking at the times other children do. Some children with 17q12 duplication also have speech delay. People with the duplication have an increased chance to have behavioral problems including autism and schizophrenia.[1][2]

People with 17q12 duplication typically have a smaller head size than other people (microcephaly). Some people with the duplication may have seizures, abnormalities of brain structures, or vision problems. In rare cases, people with the duplication may have other health concerns such as a heart defect or kidney abnormality.[2]

People with 17q12 duplication may have a wide range of signs and symptoms caused by the duplication. Even people within the same family who have the duplication may have different signs and symptoms from each other. This concept is called variable expressivity. In some cases, people who have 17q12 duplication may not have any signs or symptoms of the duplication at all. This concept is called reduced penetrance.[1]

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:
30%-79% of people have these symptoms
Cortical dysplasia
5%-29% of people have these symptoms
Abnormal vertebral morphology
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 ]

Short fingers or toes
Broad thumb
Broad thumbs
Wide/broad thumb

[ more ]

Cleft palate
Cleft roof of mouth
Cleft soft palate
Deeply set eye
Deep set eye
Deep-set eyes
Sunken eye

[ more ]

Delayed speech and language development
Deficiency of speech development
Delayed language development
Delayed speech
Delayed speech acquisition
Delayed speech development
Impaired speech and language development
Impaired speech development
Language delay
Language delayed
Language development deficit
Late-onset speech development
Poor language development
Speech and language delay
Speech and language difficulties
Speech delay

[ more ]

Downslanted palpebral fissures
Downward slanting of the opening between the eyelids
Esophageal atresia
Birth defect in which part of esophagus did not develop
Facial hypotonia
Decreased facial muscle tone
Low facial muscle tone
Reduced facial muscle tone

[ more ]

Finger syndactyly
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific

[ more ]

Language impairment
Little lower jaw
Small jaw
Small lower jaw

[ more ]

Abnormally small eyeball
Muscular hypotonia of the trunk
Low muscle tone in trunk
Peters anomaly
High levels of amniotic fluid
Self-injurious behavior
Self-injurious behaviour
Smooth philtrum

[ more ]

Toe syndactyly
Fused toes
Webbed toes

[ more ]

Tracheoesophageal fistula
Triangular face
Face with broad temples and narrow chin
Triangular facial shape

[ more ]

Percent of people who have these symptoms is not available through HPO
Autosomal dominant inheritance


The signs and symptoms of 17q12 duplication are caused by having an extra piece of genetic information on one of the chromosomes. Most people have 46 chromosomes in each cell of the body, and the chromosomes come in pairs. Therefore, there are two copies of chromosome 17. People with 17q12 duplication have an extra portion of one copy of chromosome 17.[1]

It is not known exactly why the gain of genetic information on chromosome 17 causes the signs and symptoms associated with the duplication. It is also not known why there can be such a wide range of symptoms, with some people not having any symptoms at all.[2]


The signs and symptoms of 17q12 duplication overlap greatly with the signs and symptoms of other chromosome duplications or other genetic disorders. Therefore, it would be unlikely that a doctor would suspect a person to have 17q12 duplication based on evaluating a person’s developmental or health history. In most cases, the duplication is diagnosed when a doctor orders a genetic test called a chromosomal microarray (CMA). This test looks for extra or missing pieces of chromosomes. Most people who are diagnosed with 17q12 duplication had a CMA completed based on symptoms such as intellectual disability, developmental delay, or behavioral challenges.[2]


Treatment for 17q12 duplication typically includes physical, occupational, and speech therapies. Children with the duplication may also require extra help in school. These therapies may help people with the duplication reach their full potentials. Other treatments may include behavioral therapies to manage behavioral differences such as autism.[2]

Other treatments that may be recommended for people with 17q12 duplication include antiepileptic drugs to treat seizures. Evaluations of the eyes, heart, and kidneys may also be recommended to rule out any other health problems.[2]


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

    Organizations Providing General Support

      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

      • Genetics Home Reference (GHR) contains information on 17q12 duplication. This website is maintained by the National Library of Medicine.
      • Unique is a source of information and support for families and individuals affected by rare chromosome disorders. Click on the link to view information about 17q12 duplication.

        In-Depth Information

        • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
        • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
        • 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 17q12 duplication. Click on the link to view a sample search on this topic.


          1. 17q12 duplication. Genetics Home Reference. April 2017; https://ghr.nlm.nih.gov/condition/17q12-duplication.
          2. Mefford H, Mitchell E, and Hodge J. 17q12 Recurrent Duplication. GeneReviews. February 25, 2016; https://www.ncbi.nlm.nih.gov/books/NBK344340/.
          3. 17q12 microduplications. Unique. 2013; https://www.rarechromo.org/media/information/Chromosome%2017/17q12%20microduplications%20FTNW.pdf.

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