GENE GUIDE

17p13.3 Duplication Syndrome

This guide is not meant to take the place of medical advice. Please consult with your doctor about your genetic results and health care choices. This Gene Guide was last updated on 2024. As new information comes to light with new research we will update this page. You may find it helpful to share this guide with friends and family members or doctors and teachers of the person who has 17p13.3 Duplication Syndrome.
a doctor sees a patient

17p13.3 duplication syndrome is also called 17p13.3 microduplication, or split-hand/foot malformation with long bone deficiency 3. For this webpage, we will be using the name 17p13.3 duplication syndrome to encompass the wide range of variants observed in the people identified.

What is 17p13.3 duplication syndrome?

17p13.3 duplication syndrome happens when a person has an extra piece of chromosome 17, one of the body’s 46 chromosomes. Chromosomes are structures in our cells that house our genes. The extra piece can affect learning and how the body develops.

Key Role

The 17p13.3 region plays a role in brain development.

Symptoms

17p13.3 duplication syndrome can affect communication, social, and learning skills. People who have 17p13.3 duplication syndrome may have:

  • Developmental delay
  • Intellectual disability
  • Low muscle tone
  • Autism
  • Brain changes observed on magnetic resonance imaging (MRI)
  • Intrauterine growth restriction
  • Subtle hand/foot defects

What causes 17p13.3 duplication syndrome?

17p13.3 duplication syndrome is a genetic condition, which means that it is caused by variants in genes. Our genes contain the instructions, or code, that tell our cells how to grow, develop, and work. Every child gets two copies of the 17p13.3 gene: one copy from their mother’s egg, and one copy from their father’s sperm. In most cases, parents pass on exact copies of the gene to their child. But the process of creating the egg or sperm is not perfect. A change in the genetic code can lead to physical issues, developmental issues, or both. 

Sometimes a spontaneous variant happens in the sperm, egg or after fertilization. When a brand new genetic variant happens in the genetic code is called a ‘de novo’ genetic variant. The child is usually the first in the family to have the genetic variant.

De novo variants can take place in any gene. We all have some de novo variants, most of which don’t affect our health. But because 17p13.3 plays a key role in development, de novo variants in this gene can have a meaningful effect. 

Research shows that 17p13.3 duplication syndrome is often the result of a de novo variant in 17p13.3. Many parents who have had their genes tested do not have the 17p13.3 genetic variant found in their child who has the syndrome. In some cases, 17p13.3 duplication syndrome happens because the genetic variant was passed down from a parent.

Autosomal dominant conditions

17p13.3 duplication syndrome is an autosomal dominant genetic condition. This means that when a person has the one damaging variant in 17p13.3 they will likely have symptoms of 17p13.3 duplication syndrome. For someone with an autosomal dominant genetic syndrome, every time they have a child there is a 50 percent chance they pass on the same genetic variant and a 50 percent chance they do not pass on the same genetic variant.

Do all people with 17p13.3 duplication syndrome have symptoms?

Not necessarily. Some people do not have any symptoms. Some people may not learn that they have this genetic change until it is found in their children.

Autosomal Dominant Genetic Syndrome

GENE / gene
GENE / gene
Genetic variant that happens in sperm or egg, or after fertilization
GENE / gene
Child with de novo genetic variant
gene / gene
Non-carrier child
gene / gene
Non-carrier child

Why does my child have a change in the 17p13.3 gene?

No parent causes their child’s 17p13.3 duplication syndrome. We know this because no parent has any control over the gene changes that they do or do not pass on to their children. Please keep in mind that nothing a parent does before or during the pregnancy causes this to happen. The gene change takes place on its own and cannot be predicted or stopped.

What are the chances that other family members of future children will have 17p13.3 duplication syndrome?

Each family is different. A geneticist or genetic counselor can give you advice on the chance that this will happen again in your family.

The risk of having another child who has 17p13.3 duplication syndrome depends on the genes of both biological parents. 

  • If neither biological parent has the same genetic variant found in their child, the chance of having another child who has the syndrome is on average 1 percent. This 1 percent chance is higher than the chance of the general population. The increase in risk is due to the very unlikely chance that more of the mother’s egg cells or the father’s sperm cells carry the same genetic variant. 
  • If one biological parent has the same genetic variant found in their child, the chance of having another child who has the syndrome is 50 percent. 

For a symptom-free brother or sister of someone who has 17p13.3 duplication syndrome, the sibling’s risk of having a child who has 17p13.3 duplication syndrome depends on the sibling’s genes and their parents’ genes. 

  • If neither parent has the same genetic variant causing 17p13.3 duplication syndrome, the symptom-free sibling has a nearly 0 percent chance of having a child who would inherit 17p13.3 duplication syndrome. 
  • If one biological parent has the same genetic variant causing 17p13.3 duplication syndrome, the symptom-free sibling has a 50 percent chance of also having the same genetic variant. If the symptom-free sibling has the same genetic variant, their chance of having a child who has the genetic variant is 50 percent. 

For a person who has 17p13.3 duplication syndrome, the risk of having a child who has the syndrome is about 50 percent.

How many people have 17p13.3 duplication syndrome?

As of 2024, at least 50 people with 17p13.3 duplication syndrome have been identified in medical research. The first case was found in 2009. Scientists expect to find more people who have the syndrome as access to genetic testing improves.

Do people with 17p13.3 duplication syndrome look different?

People who have 17p13.3 duplication syndrome may look different. Appearance can vary and can include some but not all of these features:

  • Low muscle tone in the face
  • Wide forehead
  • Underdeveloped cheek bones
  • Upslanting eyes
  • Broad nose bridge

How is 17p13.3 duplication syndrome treated?

Scientists and doctors have only just begun to study 17p13.3 duplication syndrome. At this point, there are no medicines designed to treat the syndrome. A genetic diagnosis can help people decide on the best way to track the condition and manage therapies. Doctors can refer people to specialists for:

  • Physical exams and brain studies
  • Genetics consults
  • Development and behavior studies
  • Other issues, as needed

A developmental pediatrician, neurologist, or psychologist can follow progress over time and can help:

  • Suggest the right therapies. This can include physical, occupational, speech, or behavioral therapy.
  • Guide individualized education plans (IEPs).

Specialists advise that therapies for 17p13.3 duplication syndrome should begin as early as possible, ideally before a child begins school.

If seizures happen, consult a neurologist. There are many types of seizures, and not all types are easy to spot. To learn more, you can refer to resources such as the Epilepsy Foundation’s website: epilepsy.com/…t-is-epilepsy/seizure-types

This section includes a summary of information from major published articles. It highlights how many people have different symptoms. To learn more about the articles, see the Sources and references section of this guide.

Behavior and development concerns linked to 17p13.3 duplication syndrome

Depending on the specific 17p13.3 duplication, the 17p13.3 region may have about 24 genes duplicated. Some people inherit the 17p13.3 duplication from a parent who may or may not have medical features.

17p13.3 duplications are divided into Class I and Class II, depending on the genes included in the duplication. The information below includes people in both categories.

Speech and Learning

People with 17p13.3 duplication syndrome had developmental delay or intellectual disability and speech delay.

  • 10 out of 13 people had developmental delay (77 percent)
  • 19 out of 29 people had intellectual disability (66 percent)
  • 4 out of 11 people had speech delay (36 percent)
77%
10 out of 13 people had developmental delay.
66%
19 out of 29 people had intellectual disability.
36%
4 out of 11 people had speech delay.

Behavior

Behavioral disorders occurred in people with 17p13.3 duplication syndrome, including autism, attention-deficit/hyperactivity disorder (ADHD), and behavioral aggression. Occasionally, obsessive-compulsive disorder and food seeking behaviors were observed.

  • 7 out of 29 people had autism (24 percent)
  • 4 out of 29 people had ADHD (14 percent)

Brain

Many people with 17p13.3 duplication syndrome reported having lower than average muscle tone. Sometimes people with 17p13.3 duplication syndrome had seizures. Brain imaging studies found defects in the corpus callosum, cerebellum, posterior fossa, and the skull. Some people had mild hypogenesis of the corpus callosum and several people had mild, nonspecific thinning of the corpus callosum.

  • 23 out of 29 people had lower than average muscle tone (79 percent)
  • 4 out of 30 people had seizures (13 percent)
Human head showing brain outline

Medical and physical concerns linked to 17p13.3 syndrome

Other findings

Some people with 17p13.3 duplication syndrome had cleft lip and palate; endocardial fibroelastosis, which is a thickening of the muscular lining of the heart; kidneys defects; abnormal thyroid findings; or hypoplasia of the penis.

  • 5 out of 29 people had cleft lip and/or palate (17 percent)

Where can I find support and resources?

Simons Searchlight

Simons Searchlight is an online international research program, building an ever growing natural history database, biorepository, and resource network of over 175 rare genetic neurodevelopmental disorders. By joining their community and sharing your experiences, you contribute to a growing database used by scientists worldwide to advance the understanding of your genetic condition. Through online surveys and optional blood sample collection, they gather valuable information to improve lives and drive scientific progress. Families like yours are the key to making meaningful progress. To register for Simons Searchlight, go to the Simons Searchlight website at www.simonssearchlight.org and click “Join Us.”

Sources and References

  • Blazejewski, S. M., Bennison, S. A., Smith, T. H., & Toyo-Oka, K. (2018). Neurodevelopmental genetic diseases associated with microdeletions and microduplications of chromosome 17p13.3. Frontiers in Genetics, 9, 80. https://pubmed.ncbi.nlm.nih.gov/29628935/
  • Farra, C., Abdouni, L., Hani, A., Dirani, L., Hamdar, L., Souaid, M., & Awwad, J. (2021). 17p13.3 microduplication syndrome: Further delineating the clinical spectrum. Journal of Pediatric Genetics, 10(3), 239-244. https://pubmed.ncbi.nlm.nih.gov/34504729/
  • Stutterd, C. A., Francis, D., McGillivray, G., Lockhart, P. J., & Leventer, R. J. (2020). Polymicrogyria associated with 17p13.3p13.2 duplication: Case report and review of the literature. European Journal of Medical Genetics, 63(4), 103774. https://pubmed.ncbi.nlm.nih.gov/31585183/
  • Vittas, S., Bisba, M., Christopoulou, G., Apostolakopoulou, L., Pons, R., & Constantoulakis, P. (2023). A case of class I 17p13.3 microduplication syndrome with unilateral hearing loss. Genes (Basel), 14(7), 1333. https://pubmed.ncbi.nlm.nih.gov/37510238/

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