22q11.2 Deletion Syndrome

What is 22q11.2 Deletion Syndrome?

22q11.2 Deletion syndrome is also known for its other name which is DiGeorge Syndrome. It is a primary immunodeficiency disease where the cause of the deficiency is genetic and could easily be noticed at birth. It will lead to problems such as the poor development of certain body systems.

The condition is receptive to infections because of the deficient function and production of the T cell, which is a white blood cell that is essential for the protection against infections.

DiGeorge Syndrome is a result of the abnormal tissue and cell formation during fetal growth and in addition to this; there is also a possibility for the development of immune system problems, defects in organs like the heart.

This problem lasts throughout a person’s life and commonly affects children and infants rather than adults or elderlies. Depending on how severe the syndrome is, the infections that occur repeatedly have the tendency to decrease in adulthood and in late childhood. However, there is still an estimation of about one-third of the affected adults will have slight recurrent infections.

What are the Symptoms of 22q11.2 Deletion Syndrome?

The symptoms of each child with 22q11.2 Deletion syndrome affect them differently and the signs can greatly vary from one another. The severity of the condition will also depend on the affected body systems and how serious the defects are.

A few symptoms might be obvious at birth, but some do not come into view until later in early childhood or infancy. Children with this syndrome usually have features such as cleft lip or palate, low-set ears, small mouth, asymmetrical shape of the skull, underdeveloped chin, and wide set of eyes.
Other signs and symptoms may include:

• Problems in respiration
• Infections that often occur
• Problem of the heart that leads to cyanosis which is the bluish discoloration of the skin caused by the bad circulation of oxygen-rich blood
• Suspended growth
• Problems with feeding and other complications of the stomach and intestine
• Postponed development of verbal communication
• Learning difficulties
• Convulsion throughout the hands, mouth, throat, or arms
• Behavioral problems
• Delayed development of infant milestones
• Failure to obtain weight gain
• Poor muscle tone

Other disorders may also be the cause of the signs and symptoms of 22q11.2 Deletion syndrome, so it is essential to get a correct diagnosis right away if a child shows any of the signs or symptoms. Do not hesitate to seek immediate medical care.

What Causes 22q11.2 Deletion Syndrome?

In most cases of 22q11.2 Deletion syndrome, the symptoms are caused by a piece of chromosome that is missing which is a genetic fault known as 22q11 deletion. The chromosomes are the ones that give instructions for the characteristics of a person. Majority of individuals have 23 pairs of chromosomes taken from their parents.

Each chromosome contains a long arm which is the ‘q’ and another arm that is shorter which is the ‘p’. In 22q11.2 deletion, a small component of the long arm is missing in chromosome 22. The 22q11.2 is accountable for numerous of conditions and syndromes; it can develop from mild form to severe form.

A lot of these genes are still not understood well. The deletion from chromosome 22 commonly happens as an unplanned event in the egg of the mother or in the sperm of the father. Sometimes it occurs during the development of the fetus and in rare cases, the deletion might be inherited from a parent who has deletions in chromosome 22 and passed onto the offspring.

How is 22q11.2 Deletion Syndrome Treated?

Treatment plans for 22q11.2 should be personalized since there is an involvement of the tissues and organs. The severity of the abnormal features also varies. In certain occasions, mild T cell problems can be treated with antibiotics and follow-ups.

Extreme cases of the syndrome where the development of the T cell is greatly affected, thymus transplant or bone marrow treatment can help. Serious problems that involve any features of the face or organs such as the heart might require corrective surgery.

In cases of children, a multi-specialty approach is a convenient treatment for them due to the associated spectrum of disorders by the problem that can be identified with various medical specialties like immunology, genetic counselling, ENT, speech therapy, and cardiology.

Life Expectancy of 22q11.2 Deletion Syndrome

For people who surpass infancy and early childhood with 22q11.2 Deletion syndrome, the life expectancy is that they can normally live with a normal life span. In most cases though, they need continuous care and treatments for other medical problems.

Families will have huge responsibilities, but there are support teams for caretakers that extend assistance to help.

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References:
1. http://www.mayoclinic.org/diseases-conditions/digeorge-syndrome/basics/causes/con-20031464
2. http://www.nhs.uk/Conditions/digeorge-syndrome/Pages/Introduction.aspx#deletion
http://www.aaaai.org/conditions-and-treatments/primary-immunodeficiency-disease/digeorge-syndrome.aspx
3. Bassett, Anne (August 2011). “Practical Guidelines for Managing Patients with 22q11.2 Deletion Syndrome”. J Pediatr 159 (2): 332–39.
4. Tonelli AR, Kosuri K, Wei S, Chick D (2007). “Seizures as the first manifestation of chromosome 22q11.2 deletion syndrome in a 40-year old man: a case report”. J Med Case Reports 1: 167.
5. Shaikh, TH; Kurahashi, H; Saitta, SC; O’Hare, AM; Hu, P; Roe, BA; Driscoll, DA; McDonald-McGinn, DM; Zackai, EH; Budarf, ML; Emanuel, BS (1 March 2000). “Chromosome 22-specific low copy repeats and the 22q11.2 deletion syndrome: genomic organization and deletion endpoint analysis.”. Human molecular genetics 9 (4): 489–501.