Chromosome 22q11.2 duplication syndrome

Symptoms

What are the main signs and symptoms of 22q11.2 duplication syndrome?

There is a lot of variability in the specific symptoms seen in individuals with 22q11.2 duplication syndrome, even within the same family. Not every individual with a 22q11.2 duplication has any known medical or developmental problems resulting from having the duplication. When a child is diagnosed with 22q11.2 duplication syndrome, it is common to offer genetic testing to that child's parents, and the 22q11.2 duplication may be found in a parent who has never had any known medical or developmental problems as a result of having the 22q11.2 duplication.

When an individual with 22q11.2 duplication has symptoms, the most common ones include developmental delay, intellectual disability, slow growth leading to short stature and weak muscle tone (hypotonia). Other symptoms include differences in heart structure or function, hearing loss and velopharyngeal insufficiency (which involves the improper closing of the roof of the mouth which can affect speech).

Because of the variability in symptoms between individuals with 22q11.2 duplication, and the possibility that a person with 22q11.2 duplication may not have any known health or developmental problems, it is not possible at the time of diagnosis, especially of a young child, to predict what symptoms, if any, that individual may have of 22q11.2 duplication syndrome, including the degree of developmental delay or intellectual disability he or she may develop, or whether he or she will be affected with any obvious issues from the 22q11.2 duplication syndrome at all.

If you have questions about whether symptoms present in yourself or a family member may be the result of a chromosome change such as 22q11.2 duplication syndrome, you may ask your primary care physician, or consult with a medical geneticist. For more information about the availability of genetic services in your area, you may ask your primary care physician or check the "Find A Genetic Counselor" directory on the National Society of Genetic Counselor website to locate genetic counselors in the United States and Canada.

References
  • Genetics Home Reference. (2011). 22q11.2 duplication. Retrieved February 20, 2016, from http://ghr.nlm.nih.gov/condition/22q112-duplication
  • Unique. (2012). 22q11.2 duplications. Retrieved February 20, 2016, from http://www.rarechromo.org/information/Chromosome%2022/22q11.2%20duplications%20FTNW.pdf
  • Firth HV. 22q11.2 Duplication. 2009 Feb 17 [Updated 2013 Nov 21]. In: Pagon RA, Adam MP, Ardinger HH, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2016. Available from: http://www.ncbi.nlm.nih.gov/books/NBK3823/
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More Symptoms Content

What specific symptoms can be seen with 22q11.2 duplication syndrome?

What additional symptoms can be seen with 22q11.2 duplication syndrome?

What changes can be seen in the heart with 22q11.2 duplication syndrome?

If you have 22q11.2 duplication syndrome will you always show symptoms?

Is it possible to have other chromosome conditions as well as the 22q11.2 duplication?

What health problems should my doctor be watching for in 22q11.2 duplication syndrome?

What other diseases look like 22q11.2 duplication syndrome?

Are there one or two characteristic "odd" or "unusual" symptom or clinical feature of 22q11.2 duplication syndrome?

What specific symptoms can be seen with 22q11.2 duplication syndrome?

Facial Features

Some individuals with 22q11.2 duplication syndrome may have distinctive (known as dysmorphic) facial features. One researcher found that when individuals with 22q11.2 duplication syndrome had distinctive facial features, the most common features were widely spaced eyes (known as hypertelorism), a broad flat nose, small lower jaw and chin (known as micrognathia), unusually formed ears, skinfolds across the inner corners of the eyes (known as epicanthal folds) and downslanting eyes. A less common feature may be tiny holes or skin tags in front of the ears.

Changes affecting the mouth

Cleft palate: Some individuals with 22q11.2 duplication syndrome are born with a condition known as cleft palate. Cleft palate is a birth defect in which the roof of the mouth (palate) doesn't form correctly and needs to be surgically closed after birth.

Velopharyngeal insufficiency: Around 70% of people with 22q11.2 duplication syndrome have been reported with velopharyngeal insufficiency (VPI), which is a disorder that results from the soft palate at the back of the mouth not forming correctly and allowing air to escape through the nose instead of the mouth. People with VPI have difficulty pronouncing most consonants correctly, including p, b, g, t and d, and their speech may also sound nasal, as if they have a chronically stuffy nose.

Hearing Loss

While most individuals with 22q11.2 duplication syndrome have normal hearing, a significant number have some hearing loss. Overall, around one child or adult in three (32/112) known to have 22q11.2 duplication has some degree of hearing loss. It is very common for children with 22q11.2 duplication syndrome to have a type of treatable hearing loss that is caused by a build-up of fluid inside the ear spaces (sometimes called glue ear, or chronic otitis media). Sensorineural hearing loss is much less common, but can also occur. This type of hearing loss is permanent and is due to damage to the inner ear (cochlea) or problems with the nerve pathways from the inner ear to the brain.

Eyesight

Individuals with 22q11.2 duplication syndrome may have droopy eyelids (ptosis), which may cause a problem with vision if the pupil of the eye is covered. Other individuals have been described to have strabismus, which is a problem in which the eyes are not aligned properly, so that one eye may be looking straight ahead while the other eye turns in a different direction. A few children (3 reported by Unique) have been reported with nystagmus, which is a jerky movement of the eyes that can be caused by a structural problem within the eye or a change in the visual pathway from the eye to the brain.

Teeth

Children with a chromosome disorder, including 22q11.2 duplication syndrome, may have a higher rate of teeth problems compared to typically-developing children. This may be due to a number of problems, such as unusual development of the teeth and/or jaw, which can lead to overcrowding or widely spaced teeth. Other issues such as problems with feeding and delayed eating and chewing activity, tooth grinding (which wears down the enamel) and widely spaced teeth may also cause tooth problems. Teeth may emerge late, and milk teeth (also known as baby teeth) may be late to fall out. Extra teeth may be found and either milk or adult teeth may be missing.

These and other symptoms that have been reported in individuals with 22q11.2 duplication syndrome may also be found in individuals with other types of chromosome changes, or as isolated issues in individuals with no known underlying chromosome or other genetic problem. If you have questions about whether health or developmental symptoms present in yourself or a family member may be related to a chromosome change such as 22q11.2 duplication syndrome, you may consult your primary care physician or a medical geneticist, who may decide whether genetic testing for chromosome changes such as 22q11.2 duplication syndrome or other possible genetic conditions is warranted.

References
  • Beiraghi, S., et al. "Three new cases of duplication 22q11. 2 with neuropsychological problems, learning disability and subtle dysmorphic features." Am J Hum Genet 75. Suppl (2004): 138.
  • Courtens, W., Schramme, I., Laridon, A. Microduplication 22q11.2: a benign polymorphism or a syndrome with a very large clinical variability and reduced penetrance? Report of two families. Am. J. Med. Genet. 146A: 758-763, 2008
  • de La Rochebrochard, C., Joly-Helas, G., Goldenberg, A., Durand, I., Laquerriere, A., Ickowicz, V., Saugier-Veber, P., Eurin, D., Moirot, H., Diguet, A., de Kergal, F., Tiercin, C., Mace, B., Marpeau, L., Frebourg, T. The intrafamilial variability of the 22q11.2 microduplication encompasses a spectrum from minor cognitive deficits to severe congenital anomalies. (Letter) Am. J. Med. Genet. 140A: 1608-1613, 2006.
  • Edelmann, L., Pandita, R. K., Spiteri, E., Funke, B., Goldberg, R., Palanisamy, N., Chaganti, R. S. K., Magenis, E., Shprintzen, R. J., Morrow, B. E. A common molecular basis for rearrangement disorders on chromosome 22q11. Hum. Molec. Genet. 8: 1157-1167, 1999.
  • Ensenauer, R. E., Adeyinka, A., Flynn, H. C., Michels, V. V., Lindor, N. M., Dawson, D. B., Thorland, E. C., Lorentz, C. P., Goldstein, J. L., McDonald, M. T., Smith, W. E., Simon-Fayard, E., Alexander, A. A., Kulharya, A. S., Ketterling, R. P., Clark, R. D., Jalal, S. M. Microduplication 22q11.2, an emerging syndrome: clinical, cytogenetic, and molecular analysis of thirteen patients.
  • Hassed, Susan J., et al. "A new genomic duplication syndrome complementary to the velocardiofacial (22q11 deletion) syndrome." Clinical genetics 65.5 (2004): 400-404
  • Lamb, A., et al. "Searching for patients with the 22q11. 2 duplication syndrome: Confirmation that some patients have phenotypic overlap with DiGeorge/velocardiofacial syndrome." Am J Hum Genet 75.Suppl (2004): 191.
  • Lundin, Johanna, et al. "22q11. 2 microduplication in two patients with bladder exstrophy and hearing impairment." European journal of medical genetics 53.2 (2010): 61-65.
  • Motavalli Mukaddes, Nahit, and Sabri Herguner. "Autistic disorder and 22q11. 2 duplication." The World Journal of Biological Psychiatry 8.2 (2007): 127-130.
  • Ou, Zhishuo, et al. "Microduplications of 22q11. 2 are frequently inherited and are associated with variable phenotypes." Genetics in Medicine 10.4 (2008): 267-277.
  • Yu, S., Cox, K., Friend, K., Smith, S., Buchheim, R., Bain, S., Liebelt, J., Thompson, E., Bratkovic, D. Familial 22q11.2 duplication: a three-generation family with a 3-Mb duplication and a familial 1.5-Mb duplication. Clin. Genet. 73: 160-164, 2008
  • Yobb, Twila M., et al. "Microduplication and triplication of 22q11. 2: a highly variable syndrome." The American Journal of Human Genetics 76.5 (2005): 865-876.
  • Unique. (2012). 22q11.2 duplications. Retrieved February 20, 2016, from http://www.rarechromo.org/information/Chromosome%2022/22q11.2%20duplications%20FTNW.pdf
  • Portnoï, MF, et al. "22q11. 2 duplication syndrome: two new familial cases with some overlapping features with DiGeorge/velocardiofacial syndromes." American Journal of Medical Genetics Part A 137.1 (2005): 47-51.
  • Sparkes, Rebecca, Judy Chernos, and Franciscus Dicke. "Duplication of the 22q11. 2 region associated with congenital cardiac disease." Cardiology in the Young 15.02 (2005): 229-231.
  • Firth HV. 22q11.2 Duplication. 2009 Feb 17 [Updated 2013 Nov 21]. In: Pagon RA, Adam MP, Ardinger HH, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2016. Available from: http://www.ncbi.nlm.nih.gov/books/NBK3823/
What additional symptoms can be seen with 22q11.2 duplication syndrome?

Digestion

Some individuals with 22q11.2 duplication syndrome experience digestion problems, such as gastroesophageal reflux (known as GERD). GERD may also be described as heartburn or acid indigestion. In reflux, stomach contents back up out of the stomach and into the esophagus and may cause a burning chest pain, a bitter ("acid") taste in the mouth, coughing and/or vomiting. The stomach contents may also be inhaled into the lungs, raising the risk of an infection known as aspiration pneumonia. GERD may be treated by diet and lifestyle changes, over the counter and prescription medications, and in some cases, a surgery known as fundoplication.

Anomalies in the Genital Area

Babies with a chromosome condition, such as 22q11.2 duplication, are more likely to have a genital anomaly than babies in the general population. These changes may be more obvious in boys. Unique (a rare chromosome support group) reports that around 11 out of 52 boys known to them with 22q11.2 duplication syndrome (approximately 20%) have a difference in their genitals. The specific changes present in these boys vary, and include a hidden penis (in which the penis is partially or completely "hidden" below the surface of the skin), hypospadias (in which the external opening normally found at the end of the penis is on the underside instead), undescended testicles (in which one or both testicles have not moved from the abdomen down into their proper position in the scrotum, which is the bag of skin hanging below the penis), blockage in the urethra (the tube leading out from the bladder through the penis) and an inguinal hernia (failure of the opening that allows the testes to descend into the scrotum during fetal life to close properly).

Breathing

Most people with 22q11.2 duplication syndrome breathe normally, however Unique (a rare chromosome support group) has reported that around five percent of individuals with 22q11.2 duplication, mostly children, have sleep apnea (in which they experience shallow breaths, or their breathing repeatedly stops and restarts, during sleep).

When these symptoms are present in an individual, it does not necessarily mean that he or she has 22q11.2 duplication syndrome, as these conditions are both found very commonly with other chromosome changes and genetic syndromes, as well as occur as isolated problems in individuals without any known chromosome changes or other health concerns. If you have questions about whether health or developmental symptoms present in yourself or a family member may be related to a chromosome change such as 22q11.2 duplication syndrome, you may consult your primary care physician or a medical geneticist, who may decide whether genetic testing for chromosome changes such as 22q11.2 duplication syndrome or other possible genetic conditions is warranted.

References
  • Beiraghi, S., et al. "Three new cases of duplication 22q11. 2 with neuropsychological problems, learning disability and subtle dysmorphic features." Am J Hum Genet 75.Suppl (2004): 138.
  • Courtens, W., Schramme, I., Laridon, A. Microduplication 22q11.2: a benign polymorphism or a syndrome with a very large clinical variability and reduced penetrance? Report of two families. Am. J. Med. Genet. 146A: 758-763, 2008
  • de La Rochebrochard, C., Joly-Helas, G., Goldenberg, A., Durand, I., Laquerriere, A., Ickowicz, V., Saugier-Veber, P., Eurin, D., Moirot, H., Diguet, A., de Kergal, F., Tiercin, C., Mace, B., Marpeau, L., Frebourg, T. The intrafamilial variability of the 22q11.2 microduplication encompasses a spectrum from minor cognitive deficits to severe congenital anomalies. (Letter) Am. J. Med. Genet. 140A: 1608-1613, 2006.
  • Edelmann, L., Pandita, R. K., Spiteri, E., Funke, B., Goldberg, R., Palanisamy, N., Chaganti, R. S. K., Magenis, E., Shprintzen, R. J., Morrow, B. E. A common molecular basis for rearrangement disorders on chromosome 22q11.2. Hum. Molec. Genet. 8: 1157-1167, 1999.
  • Ensenauer, R. E., Adeyinka, A., Flynn, H. C., Michels, V. V., Lindor, N. M., Dawson, D. B., Thorland, E. C., Lorentz, C. P., Goldstein, J. L., McDonald, M. T., Smith, W. E., Simon-Fayard, E., Alexander, A. A., Kulharya, A. S., Ketterling, R. P., Clark, R. D., Jalal, S. M. Microduplication 22q11.2, an emerging syndrome: clinical, cytogenetic, and molecular analysis of thirteen patients.
  • Hassed, Susan J., et al. "A new genomic duplication syndrome complementary to the velocardiofacial (22q11 deletion) syndrome." Clinical genetics 65.5 (2004): 400-404
  • Lamb, A., et al. "Searching for patients with the 22q11. 2 duplication syndrome: Confirmation that some patients have phenotypic overlap with DiGeorge/velocardiofacial syndrome." Am J Hum Genet 75.Suppl (2004): 191.
  • Lundin, Johanna, et al. "22q11. 2 microduplication in two patients with bladder exstrophy and hearing impairment." European journal of medical genetics 53.2 (2010): 61-65.
  • Motavalli Mukaddes, Nahit, and Sabri Herguner. "Autistic disorder and 22q11. 2 duplication." The World Journal of Biological Psychiatry 8.2 (2007): 127-130.
  • Ou, Zhishuo, et al. "Microduplications of 22q11. 2 are frequently inherited and are associated with variable phenotypes." Genetics in Medicine 10.4 (2008): 267-277.
  • Yu, S., Cox, K., Friend, K., Smith, S., Buchheim, R., Bain, S., Liebelt, J., Thompson, E., Bratkovic, D. Familial 22q11.2 duplication: a three-generation family with a 3-Mb duplication and a familial 1.5-Mb duplication. Clin. Genet. 73: 160-164, 2008
  • Yobb, Twila M., et al. "Microduplication and triplication of 22q11. 2: a highly variable syndrome." The American Journal of Human Genetics 76.5 (2005): 865-876.
  • Unique. (2012). 22q11.2 duplications. Retrieved February 20, 2016, from http://www.rarechromo.org/information/Chromosome%2022/22q11.2%20duplications%20FTNW.pdf
What changes can be seen in the heart with 22q11.2 duplication syndrome?

Unique, a rare chromosome disorder support group, reports that 18 out of their 112 known individuals with 22q11.2 duplication syndrome (around 18%) have been identified to have differences in how their heart is formed (structural birth defects), or how it functions. These reported heart problems vary in severity, ranging from clinically insignificant, mild problems, to complex, life threatening problems. The following heart problems have all been described in individuals with 22q11.2 duplication syndrome:

Coarctation of the aorta: The aorta is the main blood vessel through which the blood flows out of the heart and into the rest of the body. In this condition, the aorta is narrowed. This forces the heart to pump harder to push blood through the narrowed vessel. The problems associated with coarctation of the aorta can range from mild to severe.

Septal Defects: A septal defect is a hole in one of the muscular walls of the heart, either between the two upper chambers of the heart (atria), known as atrial septal defect (ASD), or between the two lower chambers of the heart (ventricles), known as ventricular septal defect (VSD). ASDs and VSDs are structural heart defects that are present from birth. Some septal defects may close on their own or not cause any clinical problems, where other septal defects require surgical closure to prevent damage to the heart and/or lungs.

Pulmonary stenosis: The pulmonary artery carries deoxygenated blood from the heart to the lungs. In pulmonary stenosis, the opening to this artery is unusually narrow, which means the heart has to work harder to pump blood through the narrowed valve. Depending on the amount of narrowing an individual with pulmonary stenosis has, he or she may experience no symptoms, or develop problems such as fatigue or fainting.

Mitral Valve Prolapse: The mitral valve separates the upper left heart chamber and the lower left chamber. In individuals with mitral valve prolapse this valve does not close properly and therefore a small amount of blood is leaked backwards through the valve. Sometimes individuals with mitral valve prolapse have an audible heart murmur on examination.

Persistent Ductus Arteriosus: The ductus arteriosus is a channel between the aorta and the pulmonary artery that should be open during fetal development to take blood from the aorta to the lungs. It usually closes shortly after birth. In persistent ductus arteriosus, this valve stays open, and so the lungs receive a greater volume of blood than they should, causing the heart to work harder than normal to pump the increased blood volume back out from the lungs. Persistent ductus arteriosus may be surgically corrected.

Patent Foramen Ovale: This is when a normal opening found between the two upper chambers of the heart does not close in the first year of life, as expected. When it remains open, extra blood passes from the left to the right side of the heart. Most individuals with a patent foramen ovale do not experience symptoms as a result and never require treatment.

Tetralogy of Fallot: Tetralogy of Fallot is a complex heart defect caused by the combination of four different structural problems within the heart. It results in deoxygenated blood being unable to easily get to the lungs to pick up oxygen. Some of this deoxygenated blood returns to the body without having been to the lungs to pick up oxygen. Some individuals with Tetralogy of Fallot require surgical intervention in infancy, while others are not diagnosed until later in life.

Transposition of the Great Arteries: In this condition, the two main blood vessels taking blood away from the heart are reversed (transposed), which, if left uncorrected, changes the way that blood flows throughout the body and causes a shortage of oxygen. Most babies born with transposition of the great arteries require surgery shortly after birth.

Hypoplastic Left Heart: This is a condition in which the left side of the heart is significantly underdeveloped at birth and cannot function properly. Medication and surgery, potentially including heart transplant, is necessary for babies born with hypoplastic left heart.

These heart conditions, while all reported in individuals with 22q11.2 duplication, also occur in individuals with other chromosome changes and genetic conditions, as well as occur as isolated findings in individuals with no other known health or developmental problems or underlying diagnoses. These conditions would be most commonly diagnosed and managed by a cardiologist (pediatric or adult).

References
  • Beiraghi, S., et al. "Three new cases of duplication 22q11. 2 with neuropsychological problems, learning disability and subtle dysmorphic features." Am J Hum Genet 75.Suppl (2004): 138.
  • Courtens, W., Schramme, I., Laridon, A. Microduplication 22q11.2: a benign polymorphism or a syndrome with a very large clinical variability and reduced penetrance? Report of two families. Am. J. Med. Genet. 146A: 758-763, 2008
  • de La Rochebrochard, C., Joly-Helas, G., Goldenberg, A., Durand, I., Laquerriere, A., Ickowicz, V., Saugier-Veber, P., Eurin, D., Moirot, H., Diguet, A., de Kergal, F., Tiercin, C., Mace, B., Marpeau, L., Frebourg, T. The intrafamilial variability of the 22q11.2 microduplication encompasses a spectrum from minor cognitive deficits to severe congenital anomalies. (Letter) Am. J. Med. Genet. 140A: 1608-1613, 2006.
  • Edelmann, L., Pandita, R. K., Spiteri, E., Funke, B., Goldberg, R., Palanisamy, N., Chaganti, R. S. K., Magenis, E., Shprintzen, R. J., Morrow, B. E. A common molecular basis for rearrangement disorders on chromosome 22q11.2. Hum. Molec. Genet. 8: 1157-1167, 1999.
  • Ensenauer, R. E., Adeyinka, A., Flynn, H. C., Michels, V. V., Lindor, N. M., Dawson, D. B., Thorland, E. C., Lorentz, C. P., Goldstein, J. L., McDonald, M. T., Smith, W. E., Simon-Fayard, E., Alexander, A. A., Kulharya, A. S., Ketterling, R. P., Clark, R. D., Jalal, S. M. Microduplication 22q11.2, an emerging syndrome: clinical, cytogenetic, and molecular analysis of thirteen patients.
  • Hassed, Susan J., et al. "A new genomic duplication syndrome complementary to the velocardiofacial (22q11 deletion) syndrome." Clinical genetics 65.5 (2004): 400-404
  • Unique. (2012). 22q11.2 duplications. Retrieved February 20, 2016, from http://www.rarechromo.org/information/Chromosome%2022/22q11.2%20duplications%20FTNW.pdf
If you have 22q11.2 duplication syndrome will you always show symptoms?

No, individuals with 22q11.2 duplication do not always have any identifiable health or developmental differences or symptoms known to be related to having the 22q11.2 duplication. There is a significant amount of variability in symptoms between individuals who are known to have 22q11.2 duplication syndrome, even within the same family. Since 22q11.2 duplication syndrome has been identified in individuals with no known clinical problems (health or development), it is not possible to predict at the time of diagnosis what, if any, symptoms a person with 22q11.2 duplication may develop. When a child with health or developmental problems is identified as having 22q11.2 duplication syndrome, it is common to also find the 22q11.2 duplication in a healthy parent with no known complications from the chromosome duplication.

References
  • Firth HV. 22q11.2 Duplication. 2009 Feb 17 [Updated 2013 Nov 21]. In: Pagon RA, Adam MP, Ardinger HH, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2016. Available from: http://www.ncbi.nlm.nih.gov/books/NBK3823/
  • Unique. (2012). 22q11.2 duplications. Retrieved February 20, 2016, from http://www.rarechromo.org/information/Chromosome%2022/22q11.2%20duplications%20FTNW.pdf
Is it possible to have other chromosome conditions as well as the 22q11.2 duplication?

It is possible for an individual with 22q11.2 duplication syndrome to have other chromosome changes in addition to the 22q11.2 duplication. One in seven individuals identified by Unique (a rare chromosomal support group) who have 22q11.2 duplication syndrome also have another chromosome change in addition to 22q11.2 duplication. It is possible that in some individuals with 22q11.2 duplication syndrome, some or all of the medical and developmental issues that person has, if present, may be the result of a different condition, and not the 22q11.2 duplication.

References
  • Unique. (2012). 22q11.2 duplications. Retrieved February 20, 2016, from http://www.rarechromo.org/information/Chromosome%2022/22q11.2%20duplications%20FTNW.pdf
What health problems should my doctor be watching for in 22q11.2 duplication syndrome?

Growth

Most babies with 22q11.2 duplication syndrome grow at a typical rate before birth and are born around the expected weight and length. After birth, the growth rate of some babies and children with 22q11.2 duplication may slow down. Some babies and children with 22q11.2 duplication are diagnosed with "failure to thrive" which means that they are not gaining weight at the expected rate, regardless of how much food they eat.

Development

Having a 22q11.2 duplication may increase the likelihood of developmental delay, but does not necessarily cause it. Developmental delay in children with the 22q11.2 duplication is typically mild-to moderate. Overall, two people in three reported in the medical literature with 22q11.2 duplication syndrome has experienced some delay, which may be most obvious in the areas of behaviour, responding to others, learning to move, concentrating, and/or learning to talk. However, it is possible that there are more people with a 22q11.2 duplication who have experienced no delay and never come to the attention of doctors. When an individual is diagnosed with 22q11.2 duplication syndrome, it is not possible to predict whether that individual will experience developmental problems or how severe those problems may be, including amongst affected individuals in the same family.

Gross Motor Skills

Some children with 22q11.2 duplication syndrome may experience developmental delay in gross motor skills. Specifically, a delay in being able to roll over, sit, become mobile and walk is common in individuals with 22q11.2 duplication syndrome. Low muscle tone leading to floppiness (hypotonia) is a common finding in individuals with 22q11.2 duplication syndrome, as are loose, mobile joints, which means that children may have to work harder to become mobile.

Fine Motor Skills

The possible combination of developmental delay, low muscle tone and loose joints means that children with 22q11.2 duplication syndrome are typically slow to use their hands purposefully and to coordinate hand-eye movement. As a result, babies with 22q11.2 duplication syndrome may be late to play with toys and to hold, drop and pick up objects. Affected children may also experience delays in learning how to feed themselves.

Learning

A baby born with a 22q11.2 duplication may be more likely to need learning support than a baby without the duplication. However, the range of learning difficulty is very broad and many adults and children have the duplication without experiencing any learning difficulty or disability. Even members of the same family, all with the 22q11.2 duplication, may have very different learning profiles.

Speech and Behavior

Speech and language can be the most delayed area of development for individuals with 22q11.2 duplication syndrome. It is not yet known whether any particular behavior is associated with having a 22q11.2 duplication. When behavioral problems occur, they usually involve activity levels (overactive, hyperactive), temper control, aggression and concentration. A small number of children with 22q11.2 duplication syndrome have been diagnosed with autism and more are believed to have autistic traits, such as tight adherence to routine. Other behavioral problems reported with 22q11.2 duplication syndrome include immaturity, anxiety, and poor impulse control.

Epilepsy

Twelve children within the Unique population (a rare chromosomal disorder support group) have been diagnosed with epilepsy, which is a condition where abnormal electrical activity in the brain can cause unpredictable seizures and other health problems.

Medical management of an individual diagnosed with 22q11.2 duplication syndrome may be overseen by a primary care physician or a medical geneticist. It should involve screening an affected individual for possible physical health problems reported in some individuals with 22q11.2 duplication syndrome and following up with the appropriate specialists if concerns are noted, as well as monitoring development and considering appropriate interventional therapies (i.e., physical, speech, and occupational therapy) and learning supports as needed.

References
  • Hassed, Susan J., et al. "A new genomic duplication syndrome complementary to the velocardiofacial (22q11 deletion) syndrome." Clinical genetics 65.5 (2004): 400-404
  • Motavalli Mukaddes, Nahit, and Sabri Herguner. "Autistic disorder and 22q11. 2 duplication." The World Journal of Biological Psychiatry 8.2 (2007): 127-130.; Ramelli 2008 (Clarke 2009).
  • Ensenauer, R. E., Adeyinka, A., Flynn, H. C., Michels, V. V., Lindor, N. M., Dawson, D. B., Thorland, E. C., Lorentz, C. P., Goldstein, J. L., McDonald, M. T., Smith, W. E., Simon-Fayard, E., Alexander, A. A., Kulharya, A. S., Ketterling, R. P., Clark, R. D., Jalal, S. M. Microduplication 22q11.2, an emerging syndrome: clinical, cytogenetic, and molecular analysis of thirteen patients.
  • Courtens, W., Schramme, I., Laridon, A. Microduplication 22q11.2: a benign polymorphism or a syndrome with a very large clinical variability and reduced penetrance? Report of two families. Am. J. Med. Genet. 146A: 758-763, 2008
  • Yobb, Twila M., et al. "Microduplication and triplication of 22q11. 2: a highly variable syndrome." The American Journal of Human Genetics 76.5 (2005): 865-876.
  • Yu, S., Cox, K., Friend, K., Smith, S., Buchheim, R., Bain, S., Liebelt, J., Thompson, E., Bratkovic, D. Familial 22q11.2 duplication: a three-generation family with a 3-Mb duplication and a familial 1.5-Mb duplication. Clin. Genet. 73: 160-164, 2008
What other diseases look like 22q11.2 duplication syndrome?

The most common findings in 22q11.2 duplication syndrome (ie, intellectual disability, learning disability, delayed psychomotor development, growth retardation and weak muscle tone (hypotonia)) are common and mostly nonspecific indications for genetic testing. The extent to which duplication 22q11.2 is a cause for any of these findings in an individual with 22q11.2 duplication syndrome is currently unknown.

It may be appropriate to consider further testing of a child with severe developmental problems and/or multiple congenital anomalies who has been diagnosed with 22q11.2 duplication syndrome to determine whether additional genetic diagnoses are contributing to these symptoms.

One potential area of confusion regarding changes on chromosome 22 is that in addition to 22q11.2 duplication syndrome, there is also a 22q11.2 deletion syndrome, which involves a deletion of this same region of chromosome 22. 22q11.2 deletion syndrome is well described in the medical literature and goes by many different names, and so when a change involving chromosome number 22 is being considered, it should be clearly stated whether the change being discussed is a duplication or deletion.

References
  • Firth HV. 22q11.2 Duplication. 2009 Feb 17 [Updated 2013 Nov 21]. In: Pagon RA, Adam MP, Ardinger HH, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2016. Available from: http://www.ncbi.nlm.nih.gov/books/NBK3823/
  • Unique. (2012). 22q11.2 duplications. Retrieved February 20, 2016, from http://www.rarechromo.org/information/Chromosome%2022/22q11.2%20duplications%20FTNW.pdf
Are there one or two characteristic "odd" or "unusual" symptom or clinical feature of 22q11.2 duplication syndrome?

There are no unique, odd, unusual or specific findings to 22q11.2 duplication syndrome that would enable a doctor to identify this condition in an affected individual without doing the appropriate genetic testing. The clinical spectrum of the 22q11.2 duplication syndrome is variable and no single clinical feature is required to establish the diagnosis. The most common findings in 22q11.2 duplication syndrome (intellectual disability, learning disability, delayed psychomotor development, growth retardation and weak muscle tone (hypotonia)) are nonspecific and are common findings in many other genetic conditions as well as commonly occur as isolated findings in individuals with no known underlying diagnosis.

References
  • Unique. (2012). 22q11.2 duplications. Retrieved February 20, 2016, from http://www.rarechromo.org/information/Chromosome%2022/22q11.2%20duplications%20FTNW.pdf

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