Children diagnosed with DiGeorge syndrome (DGS) have the underlying condition called 22q11.2 deletion syndrome. They are missing a small part of the chromosome 22.
Most of the time 22q11 deletion happens by chance. However, in about 10 percent of families, the deletion is inherited and other family members are affected or at risk for passing this deletion to their children. For this reason, whenever a deletion is diagnosed, both parents are offered the opportunity to have their blood studied to look for this deletion.
DiGeorge syndrome is the name for the group of symptoms caused by the missing piece of chromosome 22. Medical problems commonly seen in children with DiGeorge syndrome include heart defects, poor immune system function, a cleft palate, poor function of the parathyroid glands and behavioral disorders.
A common condition in children with DGS is a cleft palate — an opening (cleft) in the roof of the mouth (palate).
In children with DGS, the thymus gland may be small or missing, causing poor immune function and frequent, severe infections. The absence of the thymus gland distinguishes DSG from the other syndromes associated with 22q deletion.
DiGeorge syndrome can cause smaller than normal parathyroid glands. They secrete too little parathyroid hormone (PTH). This is called hypoparathyroidism. Hypoparathyroidism results in low levels of calcium and high levels of phosphorus in the blood.
DiGeorge syndrome often causes heart defects that result in an inadequate supply of blood to the body. These defects may include a hole between the lower chambers of the heart (ventricular septal defect); only one large vessel, rather than two vessels, leading out of the heart (truncus arteriosus); or a combination of four abnormal heart structures (tetralogy of Fallot).
Some people with DGS may have certain facial features. These may include small, low-set ears; wide-set eyes; hooded eyes; a relatively long face; or a short or flattened groove in the upper lip.
The 22q11.2 deletion may cause problems in the development and function of the brain, resulting in learning, social, developmental or behavioral problems. Delays in toddler speech development and learning difficulties are common. A number of children with DiGeorge syndrome develop attention-deficit/hyperactivity disorder, autism or autism-related disorders.
Other medical conditions may be linked with DiGeorge syndrome. These can include hearing impairment, poor vision and poor kidney function.
Some signs and symptoms of DGS may be noticed at birth, but others may not appear until later in infancy or early childhood. The new 22q Center at Nationwide Children’s Hospital, along with the Cleft Lip and Palate Center, provides families and their children access to a multidisciplinary team of professionals. Although there is no cure for 22q deletion syndrome, many therapies, medical and surgical treatments are available to address its associated symptoms. The earlier these symptoms are detected, the sooner treatment can be started.