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Disease Profile

15q11.2 microdeletion

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 15q11.2 microdeletion; Chromosome 15q11.2 deletion; Del(15)(q11.2);


Congenital and Genetic Diseases


15q11.2 microdeletion refers to a chromosome abnormality in which a tiny piece of genetic material on the long arm of chromosome 15 (at a location designated q11.2) is missing (deleted). The features of people with a 15q11.2 microdeletion vary widely.[1] The most common features include developmental, motor, and language delays; behavior and emotional problems; attention deficit disorders; and autism spectrum disorder.[1][2] Other features may include birth defects and seizures.[2] However, some people have no apparent physical, learning, or behavior problems.[1] A 15q11.2 microdeletion may occur randomly for the first time in an affected person, or it may be inherited from a parent. Treatment depends on the signs and symptoms in each person.


The signs and symptoms in people with a 15q11.2 microdeletion can vary widely. Some people with the microdeletion don't have any apparent features, while others are more severely affected. When not all people with a genetic abnormality are affected, the condition is said to have reduced penetrance. When signs and symptoms vary among affected people, the condition is said to have variable expressivity.[2]

The most commonly reported features in people with a 15q11.2 microdeletion include:[2]

Other signs and symptoms that have been reported include seizures; abnormally shaped ears; abnormalities of the palate (roof of the mouth); memory problems; behavioral problems; and mental illness.[2] While some babies with a 15q11.2 microdeletion are born with a minor or serious birth defect, many babies are born completely healthy.[1]

You may read additional information about this microdeletion in Unique's guide entitled '15q11.2 microdeletions.' This guide contains information from both the published medical literature and from a survey of members with a 15q11.2 microdeletion.

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:
Percent of people who have these symptoms is not available through HPO
Abnormal heart morphology
Abnormality of the heart
Abnormally shaped heart
Heart defect

[ more ]

Attention deficit hyperactivity disorder
Attention deficit
Attention deficit disorder
Attention deficit-hyperactivity disorder
Attention deficits
Childhood attention deficit/hyperactivity disorder

[ more ]

Autistic behavior
Autosomal dominant inheritance
Broad forehead
Increased width of the forehead
Wide forehead

[ more ]

Cleft palate
Cleft roof of mouth
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 ]

Feeding difficulties
Feeding problems
Poor feeding

[ more ]

Generalized hypotonia
Decreased muscle tone
Low muscle tone

[ more ]

Global developmental delay
Happy demeanor
Wide-set eyes
Widely spaced eyes

[ more ]

Incomplete penetrance
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific

[ more ]

Obsessive-compulsive behavior
Obsessive compulsive behavior
Flat head syndrome
Flattening of skull
Rhomboid shaped skull

[ more ]

Slender finger
Narrow fingers
Slender fingers
thin fingers

[ more ]



A 15q11.2 microdeletion may occur randomly for the first time in an affected person (a de novo mutation), or it may be inherited from a parent with the microdeletion. A blood test to look at the parents' chromosomes is needed to find out how the microdeletion occurred.

When a 15q11.2 microdeletion occurs as a de novo mutation, it is due to a random error either during the formation of a parent's egg or sperm cell, or very soon after conception (fertilization of the egg). A parent with the microdeletion has a 50% chance with each pregnancy to pass on the microdeletion.

The features of 15q11.2 microdeletion occur because the deleted region of the chromosome contains several genes that are important for normal growth and development. It is not yet clear why there is a large range of features and severity among people with a 15q11.2 microdeletion, or why some people are unaffected.[1]


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

    • 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 15q11.2 microdeletion.

      In-Depth Information

      • 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.
      • 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 15q11.2 microdeletion. Click on the link to view a sample search on this topic.

        Selected Full-Text Journal Articles


          1. 15q11.2 microdeletions. Unique. 2012; https://www.rarechromo.org/media/information/Chromosome%2015/15q11.2%20microdeletions%20FTNW.pdf.
          2. Cox DM, Butler MG. The 15q11.2 BP1-BP2 Microdeletion Syndrome: A Review. Int J Mol Sci. February 13, 2015; 16(2):4068-4082. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4346944/.

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