What is 22q11 deletion syndrome
22q11 deletion syndrome (22q11DS) is a genetic condition that affects about 1 in 2000 to 1 in 4000 children. 22q11DS is known by several other names including velo-cardio-facial syndrome (VCFS) and DiGeorge syndrome. 22q11DS is the second most common genetic condition after Down syndrome.
People with 22q11DS, VCFS and DiGeorge syndrome all have the same
genetic cause: a small missing piece of genetic material (DNA) on one of their two copies of chromosome 22. This missing genetic material is called a deletion.
Symptoms of 22q11DS
22q11DS can affect many parts of the body. It can also affect how a person learns. 22q11DS has a wide range of symptoms that can differ greatly from one person to another.
Only the more common features seen in people with 22q11DS are presented here.
Each child with 22q11DS is unique; it is very unlikely for a child with 22q11DS to have all of these features.
Medical features of 22q11DS
Congenital heart malformations
More than half of children with 22q11DS have heart malformations (differences in how the heart forms). Common malformations include interrupted aortic arch, tetralogy of Fallot and ventricular septal defect.
Some babies with heart malformations may need an operation soon after birth or in their first year of life.
Palate malformations
Some babies with 22q11DS are born with a cleft palate (a hole in the roof of the mouth). Others have less obvious palate malformations that result in escape of liquid, food or air through the nostrils. The term for this condition is velo-pharyngeal insufficiency (VPI). Children with cleft palate or VPI often have speech that sounds nasal (hypernasal speech) and can be difficult to understand.
Some children may need an operation to correct their cleft palate or VPI.
Immunodeficiency (weak immune system)
The immune system helps the body to fight infections. Babies with 22q11DS may experience repeated infections (such as ear infections or pneumonia), due to a weaker immune system. There are certain vaccinations called live viral vaccines that children with 22q11DS should not receive until a doctor specializing in the immune system (immunologist) tells you they are safe to give. The live viral vaccines include rotavirus, nasal influenza spray, measles-mumps-rubella (MMR), chicken pox and yellow fever.
Hypocalcemia (low blood calcium)
About half of children with 22q11DS will have lower than normal levels of calcium in their blood. Having low levels of calcium is called hypocalcemia. Calcium levels can drop when the body is under stress, such as during severe illness, surgery, puberty and pregnancy. If calcium drops to a very low level, a person can have a seizure. Chronic (long term) low calcium can lead to weaker bones.
People with 22q11DS need to have their calcium levels checked regularly (at least once a year), and should ensure they are eating calcium-rich foods. Some may need to take vitamin D or calcium supplements, and in certain cases a prescription medication to help increase their blood-calcium levels.
Thyroid function
The thyroid is a gland in the neck that helps control many functions in the body, including energy level, growth, weight, body temperature and digestion. A small number of school-aged children with 22q11DS will develop an overactive (hyperthyroidism) or underactive (hypothyroidism) thyroid that requires treatment. Thyroid function should be tested every year with a blood test.
Low platelet levels
Platelets are an important component of the blood; they stop bleeding by forming blood clots after injuries. Children with 22q11DS may develop a low platelet count, which can be checked by a blood test. Most people with a low platelet count will have no symptoms and will not need active treatment, only monitoring.
Renal (kidney) anomalies
Children with 22q11DS may be born with kidney anomalies, such as a small kidney or only a single kidney (one kidney instead of two), kidney cysts (fluid-filled pockets) or a kidney that is shaped differently. A renal ultrasound can detect these differences and help doctors decide if any treatment or monitoring is needed.
Dysphagia (swallowing and feeding difficulties)
Some infants and children with 22q11DS have feeding and swallowing difficulties because they are unable to co-ordinate the different muscles involved in swallowing. This can lead to aspiration where breast milk or formula enters the lungs. Thickened feeds or tube feeding can help babies who aspirate frequently. Most babies will have improvement of their swallowing and feeding over time, and will not require long-term tube feeding.
Gastrointestinal issues (digestive tract)
Many children with 22q11DS have problems with their digestive system. Babies can experience gastroesophageal reflux. Toddlers and children can experience chronic constipation. A pediatrician can make recommendations depending on the symptoms your child experiences.
Seizures
Seizures can occur if calcium levels drop too low (hypocalcemic seizures). These types of seizures go away when calcium levels return to normal. Seizures of no known cause are also more common in individuals with 22q11DS, and may need further investigation by a neurologist.
Dental issues
Children with 22q11DS tend to be prone to multiple cavities despite regular brushing. Regular visits to the dentist and brushing from a young age can help promote good dental health.
Hearing
Some children with 22q11DS develop mild to moderate hearing loss, which can contribute to delayed speech development. Regular hearing tests (every 1-2 years) are very important.
Vision
Some children may require glasses for reading or distance. Others may need treatment for a lazy eye or other eye problems. In general, vision problems associated with 22q11DS are not severe.
Development and learning in 22q11DS
Motor skills
Babies with 22q11DS may experience delays in reaching their gross and fine motor milestones (like rolling sitting, walking and strengthening hand grip). Many will benefit from early intervention therapy, such as occupational and physiotherapy.
Language development
Toddlers and preschool-aged children with 22q11DS almost always have delays in speech and language. In particular, expressive (spoken) language is delayed, and once children learn to speak they can be difficult to understand (articulation). On the other hand, receptive language (the ability to understand what is being said) is often better developed than expressive language. Individuals with 22q11DS may also have nasal sounding speech (VPI) Children with VPI may benefit from surgery. Most children with 22q11DS will require speech therapy in their preschool years; some may require continued therapy in elementary school.
Learning difficulties
The majority of children with 22q11DS will experience learning difficulties, and may require extra support in the classroom, especially in the areas of math and reading comprehension. Most children with 22q11DS are in a regular classroom with an individualized educational plan (IEP) that addresses their unique learning needs. Some children may need to be in a special education classroom.
Mental health
Children with 22q11DS may experience mental health disorders, such as ADHD and anxiety. As people with 22q11DS get older, they have an increased chance to develop a psychiatric disorder such as depression or psychosis. Early identification and treatment is very important, so if you notice significant changes in your child’s mood, personality or behaviour, speak to your health-care provider.