DiGeorge syndrome is a chromosomal disorder that typically affects the 22nd chromosome. Several body systems develop poorly, and there may be medical problems, ranging from a heart defect to behavioral problems and a cleft palate.
The condition is also known as 22q11.2 deletion syndrome. Around 90 percent of people with the condition have a small deletion on the 22nd chromosome at the q11.2 location.
This deletion is now known to be responsible for several previously-named syndromes that now all fall under the 22q11.2 deletion syndrome.
Other names include velocardiofacial syndrome, conotruncal syndrome, Shprintzen syndrome, and CATCH22.
DiGeorge syndrome is thought to affect 1 in 4,000 people. However, the features vary widely. As a result, underdiagnosis and misdiagnosis are likely to occur.
Fast facts on DiGeorge syndrome
Here are some key points about DiGeorge syndrome.
- DiGeorge syndrome is typically referred to as 22q11.2 deletion syndrome, as this most accurately reflects its origins
- The deletion of genes from the 22nd chromosome usually occurs randomly, and the condition is rarely inherited.
- The symptoms depend on the organ system that is affected.
- DiGeorge syndrome is often diagnosed with a specific blood test.
- Treatment will depend on the symptoms and the systems affected.
DiGeorge syndrome results from the deletion of the 22q11.2 segment in one of the two copies of chromosome 22. It affects approximately 30 to 40 genes.
Many of these genes are not yet fully understood.
The syndrome usually starts as a random event during fertilization, either on the maternal or paternal side. It may happen during the time of fetal development.
Most cases are not inherited, and there is rarely a family history of the condition.
However, in around 10 percent of cases, it is passed from a parent to a child.
If a child has DiGeorge syndrome, parents or caregivers may notice that they have:
- delays in learning to walk or talk and other developmental and learning delays
- hearing and vision problems
- mouth and feeding problems
- short stature
- frequent infections
- bone, spine, or muscle problems
- unusual facial features, including an underdeveloped chin, low-set ears, and wide-set eyes
- a cleft palate or other palate disorders
Heart problems are most likely to affect the aorta.
They may include:
- ventricular septal defect, a hole between the lower heart chambers
- truncus arteriosus, a missing heart vessel
- tetralogy of Fallot, a combination of four abnormal heart structures
The syndrome can involve a wide range of signs and symptoms.
They include:
- respiratory difficulties
- mouth, arm, throat or hand spasms
- frequent infections
- delayed growth
- poor muscle tone
- a higher risk of some behavioral problems, such as ADHD
- a higher risk later in life of some psychiatric disorders such as schizophrenia
- autoimmune diseases such as idiopathic thrombocytopenia purpura, autoimmune hemolytic anemia, autoimmune arthritis and autoimmune thyroid disease
- parathyroid gland abnormalities, usually hypoparathyroidism, causing abnormal calcium and phosphorus metabolism and sometimes seizures
- thymus gland abnormalities, such as a small, underactive thymus
- blue skin color (cyanosis), due to poor circulation caused by heart defects
Other symptoms may include hearing impairment, visual abnormalities, and altered kidney function
Due to the significant variability of DiGeorge syndrome, the type and severity of symptoms are typically determined by the organ system affected.
DiGeorge syndrome can become evident at birth, in infancy or during early childhood.
DiGeorge syndrome is most commonly diagnosed with a blood test called a FISH analysis (Fluorescent In Situ Hybridization).
A health care provider is likely to request a FISH analysis if a child has symptoms that may indicate DiGeorge syndrome, or if there are signs of a heart defect. Certain types of heart defect are strongly associated with the condition.
Source: Medical News Today
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