DiGeorge syndrome is but one of the many manifestations of a disorder that is known as 22q11.2 deletion syndrome. It is a relative newcomer to the world of known syndromes, having been first described in 1968 by Angelo DiGeorge, the American pediatric endocrinologist for whom it is named. I know DiGeorge syndrome well because a couple I know gave birth to a daughter who has it almost two years ago. She required several major heart operations and her parents also had to get her a life support system, which she still uses, although now she can move about on her own. She has only four fingers on each hand, and no bone in part of her arm. The rest of this article will be about DiGeorge syndrome in general.
Causes of DiGeorge syndrome
The most basic cause of DiGeorge syndrome is the absence of a small part of chromosome 22, which is the second smallest chromosome in human beings. This absence results in many of the body’s systems developing poorly, as will be outlined in the symptoms section. Doctors are not completely certain as to which parts are missing and what role they play.
The deletion of the chromosome can occur in either the sperm or the egg, and in most cases it occurs randomly. Sometimes it occurs very early, as the fetus is beginning to develop, so that every cell in the body carries the chromosomal defect. Sometimes the condition is inherited. In a minority of cases, the defect is on chromosome 10.
The appearance of DiGeorge’s syndrome victims vary greatly, but often the skin of the baby is bluer than that of a normal one, because its blood is low in oxygen, which contributes to its red color; this condition is known as cyanosis. DiGeorge’s also distorts the shapes and configurations of many body parts—the ears may be positioned abnormally low or the eyes abnormally high, or there may be a cleft in one or both of the lips.
Behavior is also to a great extent affected by the syndrome. The baby may not learn to walk or stand up at the same age at which the average child does, and speech development may be similarly delayed. Mental retardation is common in DiGeorge’s children.
Symptoms of DiGeorge syndrome
The immune system in many babies with DiGeorge’s syndrome does not function fully owing to its rudimentary development, often resulting in frequent infections, and the child may also have one or more heart defects, such as:
- AS ventricular septal defect, or hole between the heart’s two lower chambers
- Truncus arteriosus, which is when only a single, large vessels carries the blood away from the heart—there should normally be two of these
- The so-called tetralogy of Fallot, characterized by a combination of four heart structures that have not developed normally
Another condition that may occur in DiGeorge’s infants is known as Hypoparathyroidism. In such cases, the parathyroid glands, which help the body to maintain healthy levels of calcium and phosphorus by regulating the secretion of PTH, or parathyroid hormone, is smaller than normal. Thus the levels of calcium are too low, and those of phosphorus too high, to maintain a healthy body. These low levels of calcium, which plays a role in regulating the heartbeat, often result in defects in many body parts, such as the teeth.
During early childhood, a gland called the thymus nurtures the T cells that are needed to fight off infections. In DiGeorge’s victims this gland may be unusually small or even altogether absent, leaving the body vulnerable to infections that would otherwise be held at bay.
Other symptoms of the syndrome include eating difficulties, shortness of breath, poor muscle tone, quick fatigue , kidney malfunction and a tendency to remain at the same weight. Some victims suffer from visual or hearing impairment.
Adults with DiGeorge’s syndrome often develop psychiatric problems such as schizophrenia or anxiety more readily than other people. They may also be physically more prone to diseases such as rheumatoid arthritis or Grave’s disease. The latter is an autoimmune disease of the thyroid which can cause the heart to beat too rapidly or the muscles to become weak. The victim may also lose sleep or become nervous and irritable.
There is no cure for DiGeorge’s syndrome in the commonly accepted sense of the word, that is, a way of making the condition go away completely. However, many of the symptoms of the disease, like heart defects and low calcium levels, can be treated and moderated. Babies with DiGeorge syndrome almost always require treatment from doctors who have specialized training. It is essential for the parents of a child who has been diagnosed with DiGeorge’s to get as accurate as description of that child’s particular condition as possible. They should ask what diagnostic tests will be run and when the results of those tests will be in, which medical conditions have the highest priority, what specialists the doctors recommend, what kind of assistance they will provide in monitoring the development of the child, what services they can make use of and what educational material on DiGeorge’s will be most helpful to them.
Thymus gland dysfunction may be treated in different ways, depending on the severity. If it is a limited case, doctors may simply choose to deal with the infections the same way that they normally would. If on the other hand the dysfunction is a severe one, more drastic measures are required–thymus tissue may have to be transplanted or the patient given specialized cells from bone marrow or of the disease-combating type. Cleft palate and heart defects can usually be corrected through surgical procedures.
A whole team of medical professionals works to provide children handicapped by Di-George’s syndrome with the care that they need in order to remain alive and as close to something resembling normal as they can. These include geneticists, facial surgeons, occupational therapists, speech therapists and mental health workers, in addition to specialists in such fields as child development, children’s health, heart defects, hormone defects, infectious diseases and various surgical areas.
With the help of the speech and occupational therapists, the child can often begin to develop more closely to normal than he otherwise could. He can learn to master the social and interpersonal skills and exhibit the patterns of behavior that are appropriate for a child of his age. In some cases the handicapped child develops mental disorders, in which case psychotherapy and even prescription medications may be necessary.
The parents of a child with DiGeorge’s syndrome also need emotional support. There exist a number of organizations, such as the Velocity-Cardiovascular-Facial Syndrome Educational Foundation, that teach such people what they need to know in order to deal with the challenge. Family members and friends can also pitch in and help with the various chores that are part of raising a handicapped offspring, as well as with other tasks that need to be done. It always helps the parents to know that these people are always there for them.