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Multimedia

The portions of chromosome 22 deleted in DiGeorge syndrome play a role in the development of a number of body systems. As a result, the disorder can cause several errors during fetal development. Common problems that occur with DiGeorge syndrome include:

  • Heart defects. DiGeorge syndrome often causes heart defects that result in an insufficient supply of oxygen-rich blood for 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); and a combination of four abnormal heart structures (tetralogy of Fallot).
  • Hypoparathyroidism. The four parathyroid glands are oval, grain-of-rice-sized glands located in your neck. These glands maintain proper levels of calcium and phosphorus in your body by turning off or on the secretion of parathyroid hormone (PTH). DiGeorge syndrome can result in smaller than normal parathyroid glands that secrete too little PTH (hypoparathyroidism). Hypoparathyroidism results in low levels of calcium and high levels of phosphorus in the blood.
  • Thymus gland dysfunction. The thymus gland in children, located beneath the breastbone, is where T cells — a type of white blood cell — mature. Mature T cells are needed to help fight infections. As you grow older, the thymus decreases in size, and other parts of your body take over the role of the thymus in the immune system. In children with DiGeorge syndrome, the thymus gland may be small or missing, resulting in poor immune function and frequent, severe infections.
  • Cleft palate. A common condition of DiGeorge syndrome is a cleft palate — an opening (cleft) in the roof of the mouth (palate). Other, less visible abnormalities of the palate that may also be present can make it difficult to swallow or produce certain sounds in speech.
  • Facial features. A number of particular facial features may be present in some people with DiGeorge syndrome. 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.
  • Learning, behavioral and mental health problems. The 22q11.2 deletion may cause problems with 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 disorders, such as attention-deficit/hyperactivity disorder (ADHD), autism or autism-related disorders. Later in life people with DiGeorge syndrome are at increased risk of mental health problems, including depression, anxiety disorders, schizophrenia and other psychiatric disorders.
  • Autoimmune disorders. People who had poor immune function as children, due to a small or missing thymus, may have an increased risk of autoimmune disorders, such as rheumatoid arthritis and Graves' disease.
  • Other problems. A large number of medical conditions may be associated with DiGeorge syndrome. These include hearing impairment, poor vision, poor kidney function and relatively short stature for one's family.
Aug. 09, 2011