Monosomy 22q13.3, also known as Phelan-McDermid syndrome, is a chromosome disorder caused by the loss (deletion) of a small piece of chromosome 22. The deletion occurs near the end of the long arm (or q arm) of the chromosome at a location designated as q13.3. Not everyone with monosomy 22q13.3 will have the same medical, developmental, or behavioral problems (features). Common problems include low muscle tone (hypotonia), intellectual disability, developmental delays especially delayed or absent speech, and tendency to overheat. Children may be tall and thin. Differences in other physical features are usually mild and may include long eyelashes, down slanting eyes, large ears, ears without normal folding, bulb-like tip of nose, pointed chin, large hands, and toenails that flake off as infants and then become hard and brittle as age. Unusual behaviors may include mouthing or chewing on non-food items, decreased perception of pain, and autistic-like behaviors such as flapping of hands and repetitive motions. Most reported cases of monosomy 22q13.3 are caused by 22q13.3 deletions, which usually includes many genes. The loss or the variation of a particular gene on chromosome 22, called the SHANK3 gene, is likely responsible for many of the common features associated with monosomy 22q13.3, especially intellectual disability, speech problems, low muscle tone, and developmental delay. Additional genes within the deleted area probably contribute to other features of the syndrome. In most cases, a larger deletion increases the number and severity of associated features, especially the severity of low muscle tone, developmental delay, differences in physical features, speech, and autism-like behavior. Smaller deletions located closer to the tip of the 22q seem to be associated with fewer medical, developmental, and behavioral problems.
Summary
Monosomy 22q13.3, also known as Phelan-McDermid syndrome, is a chromosome disorder caused by the loss (deletion) of a small piece of chromosome 22. The deletion occurs near the end of the long arm (or q arm) of the chromosome at a location designated as q13.3. Not everyone with monosomy 22q13.3 will have the same medical, developmental, or behavioral problems (features). Common problems include low muscle tone (hypotonia), intellectual disability, developmental delays especially delayed or absent speech, and tendency to overheat. Children may be tall and thin. Differences in other physical features are usually mild and may include long eyelashes, down slanting eyes, large ears, ears without normal folding, bulb-like tip of nose, pointed chin, large hands, and toenails that flake off as infants and then become hard and brittle as age. Unusual behaviors may include mouthing or chewing on non-food items, decreased perception of pain, and autistic-like behaviors such as flapping of hands and repetitive motions. Most reported cases of monosomy 22q13.3 are caused by 22q13.3 deletions, which usually includes many genes. The loss or the variation of a particular gene on chromosome 22, called the SHANK3 gene, is likely responsible for many of the common features associated with monosomy 22q13.3, especially intellectual disability, speech problems, low muscle tone, and developmental delay. Additional genes within the deleted area probably contribute to other features of the syndrome. In most cases, a larger deletion increases the number and severity of associated features, especially the severity of low muscle tone, developmental delay, differences in physical features, speech, and autism-like behavior. Smaller deletions located closer to the tip of the 22q seem to be associated with fewer medical, developmental, and behavioral problems.Monosomy 22q13.3, also known as Phelan-McDermid syndrome, is a chromosome disorder caused by the loss (deletion) of a small piece of chromosome 22. The deletion occurs near the end of the long arm (or q arm) of the chromosome at a location designated as q13.3. Not everyone with monosomy 22q13.3 will have the same medical, developmental, or behavioral problems (features). Common problems include low muscle tone (hypotonia), intellectual disability, developmental delays especially delayed or absent speech, and tendency to overheat. Children may be tall and thin. Differences in other physical features are usually mild and may include long eyelashes, down slanting eyes, large ears, ears without normal folding, bulb-like tip of nose, pointed chin, large hands, and toenails that flake off as infants and then become hard and brittle as age. Unusual behaviors may include mouthing or chewing on non-food items, decreased perception of pain, and autistic-like behaviors such as flapping of hands and repetitive motions. Most reported cases of monosomy 22q13.3 are caused by 22q13.3 deletions, which usually includes many genes. The loss or the variation of a particular gene on chromosome 22, called the SHANK3 gene, is likely responsible for many of the common features associated with monosomy 22q13.3, especially intellectual disability, speech problems, low muscle tone, and developmental delay. Additional genes within the deleted area probably contribute to other features of the syndrome. In most cases, a larger deletion increases the number and severity of associated features, especially the severity of low muscle tone, developmental delay, differences in physical features, speech, and autism-like behavior. Smaller deletions located closer to the tip of the 22q seem to be associated with fewer medical, developmental, and behavioral problems.
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Resource(s) for Medical Professionals and Scientists on This Disease:
RARe-SOURCE™offers rare disease gene variant annotations and links to rare disease gene literature.
GeneReviewsprovides clinical information on genetic diseases, including diagnosis, treatment, and genetic counseling.
About Phelan-mcdermid syndrome
Many rare diseases have limited information. Currently, GARD aims to provide the following information for this disease:
Population Estimate:This section is currently indevelopment.
Symptoms:May start to appear as a Newborn and as an Infant.
Cause:This disease is caused by changes to the number or structure of a person’s chromosomes.
Organizations:Patient organizations are available to help find a specialist, or advocacy and support for this specific disease.
Phelan-mcdermid syndrome is caused by genetic mutations, also known as pathogenic variants. Genetic mutations can be hereditary, when parents pass them down to their children, or they may occur randomly when cells are dividing. Genetic mutations may also result from contracted viruses, environmental factors, such as UV radiation from sunlight exposure, or a combination of any of these. Learn more about genetic diseases from the National Library of Medicine (NLM).
If you suspect you may have this disease, you may want to start collecting your family health history. Information such as other family members who have had similar symptoms, when their/your symptoms first appeared, or exposures to any potential disease-causing environmental factors should be discussed with your medical team. This tool from the Surgeon General can help you collect your family health history.
When Do Symptoms of Phelan-mcdermid syndrome Begin?
Symptoms of this disease may start to appear as a Newborn and as an Infant.
The age symptoms may begin to appear differs between diseases. Symptoms may begin in a single age range, or during several age ranges. The symptoms of some diseases may begin at any age. Knowing when symptoms may have appeared can help medical providers find the correct diagnosis.
Prenatal
Before Birth
Newborn Selected
Birth-4 weeks
Infant Selected
1-23 months
Child
2-11 years
Adolescent
12-18 years
Adult
19-65 years
Older Adult
65+ years
Symptoms may start to appear as a Newborn and as an Infant.
Symptoms
The types of symptoms experienced, and their intensity, may vary among people with this disease. Your experience may be different from others. Consult your health care team for more information.
The following describes the symptom(s) associated with this disease along with the corresponding body system(s), description, synonyms, and frequency (Note: Not all possible symptoms may be listed):
Musculoskeletal System Musculoskeletal System
49 Symptoms
49 Symptoms
49 Symptoms
Musculoskeletal System
The musculoskeletal system is made up of the bones, muscles, and joints. Common symptoms of problems in the musculoskeletal system include pain, weakness, stiffness, noises in the joints, inflammation, and decreased range of motion. Diseases affecting the musculoskeletal system may be diagnosed and treated by an orthopedist, rheumatologist, or neuromuscular specialist.
Medical Term
Accelerated skeletal maturation
Frequency
Uncommon
Very frequent
Very frequent
Always
Description
An abnormally increased rate of skeletal maturation. Accelerated skeletal maturation can be diagnosed on the basis of an estimation of the bone age from radiographs of specific bones in the human body.
On average, it takes more than six years to receive an accurate rare disease diagnosis. Many primary care providers (PCPs) may not be familiar with rare diseases, and you may need to see multiple specialists to reach the correct diagnosis. However, advocating for yourself with your healthcare team may help speed your time to diagnosis. To combat common challenges, be prepared:
Find disease-specific information to discuss with your healthcare providers.
Ask for diagnostic tests.
Request referrals to specialists.
Knowing where to start your diagnostic journey and how to navigate the next steps are critical to speeding your time to diagnosis
Your Diagnostic Team
How can a diagnostic team help?
Establishing care with a dedicated primary care provider (PCP) is an important early step in your rare disease journey. A PCP can help improve care and shorten the time to diagnosis by providing referrals to the appropriate specialists. These specialists, with advanced training in different body systems or types of diseases, can offer the specialized diagnostic procedures you need.
Diagnostic teams for Phelan-mcdermid syndrome may include:
Multidisciplinary Care Centers
Is it time to find a multidisciplinary care center?
If you've visited your PCP, met with specialists, and undergone the recommended tests, but still do not have a confirmed diagnosis, it may be time to visit a multidisciplinary care center. Multidisciplinary care centers are usually teaching, university, or research hospitals that have teams of medical experts and specialists working together in the same location. This means a wide range of diagnostic tests and clinical knowledge are available at one facility, which can help increase communication and collaboration among your care team. The additional resources often available at multidisciplinary centers may help speed the time to diagnosis for rare diseases.
Is it time to find a multidisciplinary care center?
If you've visited your PCP, met with specialists, and undergone the recommended tests, but still do not have a confirmed diagnosis, it may be time to visit a multidisciplinary care center. Multidisciplinary care centers are usually teaching, university, or research hospitals that have teams of medical experts and specialists working together in the same location. This means a wide range of diagnostic tests and clinical knowledge are available at one facility, which can help increase communication and collaboration among your care team. The additional resources often available at multidisciplinary centers may help speed the time to diagnosis for rare diseases.
If a diagnosis remains unknown despite extensive efforts by your PCP and specialists, it can be challenging to know what kind of expert you may need or where to find one. A rare disease expert is a care provider that has knowledge or training on specific disease(s), but there may only be a few experts in your state, region, or country. Rare disease experts may work at large research or teaching hospitals. In complex cases, coordinating with a network of experts can help your care provider find the right diagnosis. Contact a GARD Information Specialist for help finding an expert.
You can ask your care providers for help finding an expert or use directory tools to search for experts near you. The National Organization for Rare Disorders (NORD) maintains a list of rare disease centers with experts that work together to find treatments and cures for a broad range of rare diseases. Search NORD's Center Directory to find experts near you.
Rare Disease Experts
How can you find a rare disease expert?
If a diagnosis remains unknown despite extensive efforts by your PCP and specialists, it can be challenging to know what kind of expert you may need or where to find one. A rare disease expert is a care provider that has knowledge or training on specific disease(s), but there may only be a few experts in your state, region, or country. Rare disease experts may work at large research or teaching hospitals. In complex cases, coordinating with a network of experts can help your care provider find the right diagnosis. Contact a GARD Information Specialist for help finding an expert.
You can ask your care providers for help finding an expert or use directory tools to search for experts near you. The National Organization for Rare Disorders (NORD) maintains a list of rare disease centers with experts that work together to find treatments and cures for a broad range of rare diseases. Search NORD's Center Directory to find experts near you.
Find Your Community
How Can Patient Organizations Help?
Patient organizations can help patients and families connect. They build public awareness of the disease and are a driving force behind research to improve patients' lives. They may offer online and in-person resources to help people live well with their disease. Many collaborate with medical experts and researchers.
Services of patient organizations differ, but may include:
Ways to connect to others and share personal stories
Easy-to-read information
Up-to-date treatment and research information
Patient registries
Lists of specialists or specialty centers
Financial aid and travel resources
Please note: GARD provides organizations for informational purposes only and not as an endorsement of their services. Please contact an organization directly if you have questions about the information or resources it provides.
Clinical studies are part of clinical research and play an important role in medical advances, including for rare diseases. Through clinical studies, researchers may ultimately uncover better ways to treat, prevent, diagnose, and understand human diseases.
What Are Clinical Studies?
Clinical studies are medical research involving people as participants. There are two main types of clinical studies:
Clinical trials determine if a new test or treatment for a disease is effective and safe by comparing groups receiving different tests/treatments.
Observational studies involve recording changes over time among a specific group of people in their natural settings.
People participate in clinical trials for many reasons. People with a disease may participate to receive the newest possible treatment and additional care from clinical study staff as well as to help others living with the same or similar disease. Healthy volunteers may participate to help others and to contribute to moving science forward.
To find the right clinical study we recommend you consult your doctors, other trusted medical professionals, and patient organizations. Additionally, you can use ClinicalTrials.gov to search for clinical studies by disease, terms, or location.
What if There Are No Available Clinical Studies?
ResearchMatch helps connect people interested in research studies with researchers from top medical centers across the United States. Anyone from the U.S. can register with this free program funded by NIH. Researchers from participating institutions use the database to search for and invite patients or healthy volunteers who meet their study criteria to participate.
Join the All of Us Research Program!
The All of Us Research Program is inviting 1 million people from all backgrounds across the U.S. to help build one of the most diverse health databases in history. Researchers will use the data to learn how our biology, lifestyle, and environment affect health. This may one day help them find ways to treat and prevent diseases.
What Are Clinical Studies?
Clinical studies are medical research involving people as participants. There are two main types of clinical studies:
Clinical trials determine if a new test or treatment for a disease is effective and safe by comparing groups receiving different tests/treatments.
Observational studies involve recording changes over time among a specific group of people in their natural settings.
People participate in clinical trials for many reasons. People with a disease may participate to receive the newest possible treatment and additional care from clinical study staff as well as to help others living with the same or similar disease. Healthy volunteers may participate to help others and to contribute to moving science forward.
To find the right clinical study we recommend you consult your doctors, other trusted medical professionals, and patient organizations. Additionally, you can use ClinicalTrials.gov to search for clinical studies by disease, terms, or location.People participate in clinical trials for many reasons. People with a disease may participate to receive the newest possible treatment and additional care from clinical study staff as well as to help others living with the same or similar disease. Healthy volunteers may participate to help others and to contribute to moving science forward.
To find the right clinical study we recommend you consult your doctors, other trusted medical professionals, and patient organizations. Additionally, you can use ClinicalTrials.gov to search for clinical studies by disease, terms, or location.
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What if There Are No Available Clinical Studies?
ResearchMatch helps connect people interested in research studies with researchers from top medical centers across the United States. Anyone from the U.S. can register with this free program funded by NIH. Researchers from participating institutions use the database to search for and invite patients or healthy volunteers who meet their study criteria to participate.
Join the All of Us Research Program!
The All of Us Research Program is inviting 1 million people from all backgrounds across the U.S. to help build one of the most diverse health databases in history. Researchers will use the data to learn how our biology, lifestyle, and environment affect health. This may one day help them find ways to treat and prevent diseases.
ClinicalTrials.gov, an affiliate of NIH, provides current information on clinical research studies in the United States and abroad. Talk to a trusted doctor before choosing to participate in any clinical study. We recommend checking this site often and searching for studies with related terms/synonyms to improve results.
Contact a GARD Information Specialist if you need help finding more information on this rare disease or available clinical studies. Please note that GARD cannot enroll individuals in clinical studies.
Use the contact form to send your questions to a GARD Information Specialist.
Please allow 2 to 10 business days for us to respond.
ClinicalTrials.gov, an affiliate of NIH, provides current information on clinical research studies in the United States and abroad. Talk to a trusted doctor before choosing to participate in any clinical study. We recommend checking this site often and searching for studies with related terms/synonyms to improve results.
Contact a GARD Information Specialist if you need help finding more information on this rare disease or available clinical studies. Please note that GARD cannot enroll individuals in clinical studies.
Use the contact form to send your questions to a GARD Information Specialist.
Please allow 2 to 10 business days for us to respond.
GARD collects data from a variety of sources to populate its website and provide accurate and reliable information on rare diseases.
GARD uses data collected from Orphanet and Online Mendelian Inheritance in Man (OMIM) to interpret and provide information on rare diseases. This includes names, synonyms, genes, symptom frequency, population estimates and more.
Orphanet is an online database of rare diseases and orphan drugs that provides aggregated data coordinated by INSERM-US14 in Paris.
