Velocardiofacial (VCF) syndrome refers to areas of the body that can be affected.
Velo refers to the palate (roof of the mouth). Babies with VCF are at an increased risk of being born with a cleft palate. The palate may also have poor muscle movement. Both these features put a child at risk for speech problems.
Cardio refers to the heart. Babies with VCF are at an increased risk for being born with a heart defect.
Facial refers to the common facial features. There may be minor differences in facial features like the eyes, ears and nose that will probably not be apparent except to someone experienced with the syndrome.
The name 22q11.2 deletion refers to the area of the chromosome that is deleted in most people (80%) that have this syndrome. Chromosomes have a central region called a centromere, and 2 “arms” on either side of it (the p arm and q arm.) P stands for petite, the French word for small, and indicates the smallest arm. There is no reason for the other arm being called q except that it is the next letter in the alphabet after p. The chromosomes have bands on them when they are stained, and these bands are numbered. The VCF region is 22q11.2. 22 refers to chromosome 22, q means it is on the long arm, and 11.2 refers to the band on the long arm.
The name DiGeorge syndrome may be used when a person has all of the following absent/dysfunctional thymus leading to lower immune response (more frequent infections) and a heart defect. It was once thought that DiGeorge and VCF were completely separate syndromes it is now known that many people with DiGeorge and most people with VCF have a 22q11.2 deletion.
Will my child have all these features?
Not necessarily. This is a variable condition. Someone with VCF may have all or most of the features or they may have very few of the features.
Children with VCF can have various other problems, including learning difficulties and frequent ear and sinus infections. They are also at an increased risk for scoliosis (curvature of the spine). The most likely time for scoliosis to occur is during a growth spurt, so it is important to have regular check-ups by the pediatrician while your child is growing. It is possible to prevent or reduce the problem of scoliosis by wearing a back brace or by surgery if it is caught in time. A minor feature of VCF concerns the fingers. The children with VCF often have fingers that are more slender, tapered and hyperextensible compared to other family members. A more serious complication is the risk for psychiatric problems. Whilst 10% of people with VCF have psychiatric problems, 90% will not. If these are going to occur, they tend to start during the teenage years. It is not possible to look at babies with VCF and say which will have scoliosis, learning problems or psychiatric problems. Other problems such as cleft palate or a heart defect will be present at birth.
Is there a test for VCF?
There is a test that identifies about 80% of people thought to have VCF. VCF is caused by a loss of genetic material (deletion) on chromosome 22. A routine chromosome study will not pick up this missing bit of chromosome 22, because it is too small to see. A special test called a FISH (fluorescent in situ hybridization) study has to be used. Both these tests are done by taking a blood sample and looking at chromosome 22. The majority of people with VCF are missing this part of the chromosome on one of their chromosome 22’s.
To do the FISH study the lab uses probes (bits of DNA) that are labeled, and will stick to the VCF region. If the probe only sticks to the VCF region on one of the two chromosome 22s then you confirm the diagnosis of VCF.
Can VCF occur more than once in a family?
Most of those with VCF have a change of their chromosome 22 that occurred for the first time in them. The chance that their parents could have another child with VCF is very small, since the parents don’t have this change.
If you have VCF, then there is a 1 in 2 (50%) chance for each pregnancy that your child will also have VCF. This is because a parent with VCF has one normal chromosome 22 and one changed chromosome. When you have a baby you only pass on one of each pair of your chromosomes. If you pass on the normal chromosome then the baby will not have VCF, if you pass on the chromosome with a change, then the child will have VCF.
You have no control over which chromosome you pass on. It is like flipping a coin. You could get all heads, all tails or a mixture.
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- McDonald-McGinn D.M., Kirschiner R., et al.: The Philadelphia Story: The 22q11.2 Deletion:Report on 250 Patients. Genetic Counseling 1999; 10(1) 11-24.
- Online Mendelian Inheritance in Man, OMIM (TM). Johns Hopkins University, Baltimore, MD. MIM Number: 192430: 2002.
- Shprintzen R.J.: Velocardiofacial syndrome. Otolaryngology clinics of North America 2000; 33(6) 1217-1240.