DiGeorge syndrome, also known as 22q11.2 deletion syndrome, is a disease in which one part of the 22nd chromosome is lost, leading to a broad range of developmental problems. The types of problems that are associated with DiGeorge syndrome include:
- Heart defects
- Poor immune function
- Cleft palate
- Low blood calcium levels
- Delayed development
- Behavioral and emotional problems
Causes of DiGeorge Syndrome
Each individual has two copies of each chromosome, one of which is inherited from the mom and the other from the dad. In patients with DiGeorge syndrome, one of the inherited copies of chromosome 22 (known as 22q11.2) loses a region that encompasses 30 to 40 genes.
So, why is this region lost?
The reason why this region is deleted from chromosome 22 is because a random event occurs early during fetal development. In rare cases, the deletion can be genetically transmitted but for the most part, the deletion is random and there is nothing you can do to prevent it.
Symptoms of DiGeorge syndrome
While the cause of DiGeorge syndrome is always the same, a deletion on chromosome 22, the number of symptoms and the severity of them vary from person to person. While symptoms develop around the time of birth, many appear later on in life. The symptoms associated with DiGeorge syndrome include:
- Heart murmur
- Bluish skin due to a lack of oxygen-rich blood
- Frequent contraction of infections
- Specific facial features (i.e. underdeveloped chin, ears that are low-set, eyes that are wide-set and a grove in the lip)
- Cleft palate or other palate-related issues
- Retarded growth with delayed speech development
- Nasally speech
- Problems eating, inability to gain weight, gastrointestinal issues
- Issues with breathing
- Weak muscle tone
- Behavioral issues
- Learning disabilities
When should we go see a doctor?
Unfortunately, because the symptoms associated with DiGeorge syndrome are very common, it’s almost impossible to get an accurate diagnosis early on in the disease. The doctor may suspect that your baby has DiGeorge syndrome at birth if the child has a severe heart defect, cleft palate and other symptoms that are characteristics of the disease. Then, the doctor will carry out diagnostic tests before your child is discharged. Another time that the doctor may suspect your baby has DiGeorge syndrome is if your baby presents with illnesses and symptoms that are suggestive of the disease. This is why it’s important to attend routine medical checkups with a pediatrician.
Diagnosis of DiGeorge syndrome
DiGeorge syndrome is diagnosed based on a laboratory test that looks for deletions in the region of chromosome 22. The reason why your doctor will order this test is that they suspect your child has DiGeorge syndrome based two main factors:
- Combination of syndromes and medical issues that are suggestive of DiGeorge syndrome.
- There is a heart defect, as specific heart defects are associated with DiGeorge syndrome.
In some instances, a child may present with issues that suggest the patient may have DiGeorge syndrome, but the test may not pick a chromosome 22 deletion.
Treatment of DiGeorge syndrome
Unfortunately, there is no cure for DiGeorge syndrome. Treatments are focused on symptom management or treating other medical conditions associated with DiGeorge syndrome such as heart defects or cleft palate. The following treatments can be administered to patients with DiGeorge syndrome:
- For heart defects, patients have to undergo surgery as soon as they born to repair the heart defect and restore oxygen-rich blood back to circulation.
- Hypoparathyroidism, a disease in which patients have too little parathyroid hormone, is managed through calcium and vitamin D supplements.
- For issues with function of the thymus gland (where some immune cells develop), frequently contracted infections (such as cold or ear infection), are treated normally. Additionally, despite having limited thymus function, these kids still follow a regular vaccine schedule and most children find that their immune system improves as they get older.
- For children with significant dysfunction of the thymus to the point where there is too much damage to the thymus or it’s not even there, children are at a high risk of severe infections. In this case, children are treated using transplants of thymus tissue or specialized cells that help fight infections.
- Treatment of cleft palate or any other palate or lip abnormalities are generally repaired with surgery.
- For a wide range of issues surrounding development, your child can get several different types of therapies to improve their condition such as speech therapy, occupational therapy and developmental therapy. You should consult your doctor about the available types of therapies.
- Mental health or behavioral issues are monitored and managed as needed. Treatment for mental health issues, such as if your child has been diagnosed with attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder, depression, or mental health condition, can be managed through a specialist using therapy and medicine.
- Other conditions that may need to be addressed include feeding problems, growth issues, hearing problems, vision changes and other medical issues.
Sources & Links
- Lindsay, E. A., Botta, A., Jurecic, V., Carattini-Rivera, S., Cheah, Y. C., Rosenblatt, H. M., ... & Baldini, A. (1999). Congenital heart disease in mice deficient for the DiGeorge syndrome region. Nature, 401(6751), 379.
- Wilson, D. I., Goodship, J. A., Burn, J., Cross, I. E., & Scambler, P. J. (1992). Deletions within chromosome 22q11 in familial congenital heart disease. The Lancet, 340(8819), 573-575.
- Marino, B., Digilio, M. C., Toscano, A., Giannotti, A., & Dallapiccola, B. (1999). Congenital heart defects in patients with DiGeorge/velocardiofacial syndrome and del22q11. Genetic counseling (Geneva, Switzerland), 10(1), 25-33.
- Photo courtesy of SteadyHealth