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