The 22q11.2 deletion syndrome is a condition caused by a missing section of chromosome 22. It is also called DiGeorge Syndrome or Velo-Cardio-Facial Syndrome.
What is 22q Deletion?
This condition is almost as common as Down syndrome. Missing a section of chromosome 22 has the potential to affect many parts of the body and can cause a wide range of health problems, so individuals with 22Q deletion may experience different symptoms. The key characteristics of this syndrome can include problems with the heart and/or kidneys, slower physical growth than others, problems with feeding and digestion, a cleft palate, a weakened immune system, hearing loss, difficulty learning new skills, challenging behaviors, and developmental delays, such as not walking or talking on time.
There is no cure for the 22q11.2 deletion, but many therapies and medical interventions are available to help address symptoms. Treatment may be received from a variety of providers, including audiologists, cardiologists, psychologists, and neurologists.
What are Effects of Velocardiofacial Syndrome?
22q11.2 microdeletion syndrome is the most complete and descriptive name for this condition, which is caused by a small missing portion of a chromosome. The DNA in people is stored in 46 packages of groups of genes, and each of these packages is known as a chromosome. The description of 22q11.2 means that the missing piece is on chromosome number 22 and that it is missing from the position “q11.2.” Chromosome number 22 contains about 1,100 genes, and in this condition, about 30 are missing.
The syndrome affects about one in 4,000 children, and most children affected by this condition do not have it passed from either parent. People with the condition can, however, pass it on to their children, and the way it is passed on is called autosomal dominant, which means that there is a 50% chance of passing on the condition to each child.
Because it was originally described as different conditions by different people, it is difficult to say who first described it, but DiGeorge syndrome was described by Angelo DiGeorge in 1968, and velocardiofacial syndrome was described by Robert Shprintzen in 1978. Many people still consider the condition as two separate entities, giving the name DiGeorge Syndrome to patients who have mainly immunological problems from the condition and using the name Velocardiofacial Syndrome to patients who have heart defects at birth.
The kinds of heart defects include:
- Septal defects – A “hole in the heart” exists between the left and right sides.
- Persistent truncus arteriosus – There is a single artery out of the heart instead of one to the lungs and one to the rest of the body.
- Interrupted aortic arch – The main artery carrying blood to the lower half of the body has a missing section.
- Tetralogy of Fallot – An imbalance between the two sides of the heart causes a series of heart defects.
The end result of these is that the amount of oxygen carried around the body by the blood is reduced, and surgery at a young age is often required.
Failure of the immune system in this condition is rare, although a degree of malfunction is seen fairly frequently, which means that infections can be harder to fight. This is because of a gland in the lower neck called the thymus, which has an important role in childhood. The thymus allows certain immune cells known as “T-cells” to mature, but when it functions poorly, these cells do not work as well as they should in early years.
Before adulthood, the thymus tends to shrink away, and other parts of the body take over its function. Most children with this condition who have a degree of immune malfunction tend to have a poorly functioning thymus, but the immune malfunction in early years tends to improve over time as other parts of the body take over that role. Along with the poorly functioning thymus, children with this condition can have problems with maintaining the correct amount of calcium in the blood because the glands that control this, called the parathyroid glands, also often do not work well. This can result in a variety of problems with bones, hair, nails, skin and teeth.
A cleft palate, if there is one, can cause problems with feeding immediately after birth. In fact, children with velocardiofacial syndrome commonly have problems with feeding. A cleft palate is a hole in the roof of the mouth that can prevent children from forming adequate suction in their mouth to be able to feed. As a result, children will need special bottles or nipples to be able to feed well. Your child’s feeding pattern can be assessed by our speech pathologists who will recommend the ideal combination of feeding equipment for your child.
Repairing the cleft palate is recommended. A well-functioning palate is required to produce most of the sounds that we make during speech, and children who do not have their palate repaired have difficulty with speech and with being understood. More detail on this can be found in the cleft palate page. Children with velocardiofacial syndrome appear to have further problems developing good speech, and so may require further surgery and speech therapy over and above other children who have a cleft palate without this condition.
Children with this condition can have difficulties with learning, which can be due to problems with hearing, behavioral issues because IQ tends to be within the low end of the normal range or because of a combination of these factors. Although most people with velocardiofacial syndrome will not develop psychiatric illness, there is a higher chance of having psychiatric problems than in people without velocardiofacial syndrome.
The face of children with velocardiofacial syndrome tend to show some characteristic features, although these tend to be fairly subtle. Most parents don’t notice them until they attend a clinic or group with other children who have the condition. That’s when they typically start to notice some similarities between the children. The features can include:
- Flatness over the cheekbone area
- A broad bridge of the nose with a wide or round tip of the nose
- Ears lower on the head than expected, often with a more square or notched shape to the upper part of the ear
- Eyelids that slant downward to the outside of the face with eyelids that can form a hood over the eyelashes
- Eyes that are unusually widely set apart, and a mouth that is slightly open at rest
It is difficult to say how children will be affected by the condition and what they can expect throughout their childhood as individual children are affected in very different ways, both in terms of which parts of the body are affected and also how severely they are affected.