22q11.2 Deletion Syndrome

Introduction

22q11.2 deletion syndrome is a disorder that involves many different areas of the body and can vary greatly in severity among people with the condition. Signs and symptoms may include: cleft palate, heart defects, recurrent infections, unique facial characteristics, feeding problems, kidney abnormalities, hypoparathyroidism, thrombocytopenia, scoliosis, hearing loss, developmental delay, and learning disabilities. People with this condition are also more likely to develop certain autoimmune disorders and personality disorders. 22q11.2 deletion syndrome is caused by a deletion of a small part of chromosome 22near the middle of the chromosome at a location known as q11.2. In most cases, the syndrome occurs for the first time in the affected person; about 10% of cases are inherited from a parent. It is inherited in an autosomal dominant manner. Although there is no specific treatment or cure, there can be ways to manage the symptoms. A team of doctors is often needed to figure out the treatment options based on each person’s symptoms.


Symptoms

The signs and symptoms of 22q11.2 deletion syndrome vary greatly from person to person, even among affected people in the same family. The most common symptoms include:^[

• Heart defects (74% of individuals)
• Abnormalities with the development of the palate (69% of individuals)
• Characteristic facial features (elongated face, almond-shaped eyes, wide nose, and small ears)
• Learning difficulties (70-90% of individuals)
• Immune system problems (77% of individuals)

Additional symptoms may include:

• Low levels of calcium (50% of individuals)
• Significant feeding problems
• Kidney anomalies (31% of individuals)
• Hearing loss
• Issues with the development of the larynx, trachea, and esophagus (laryngotracheoesophageal anomalies)
• Growth hormone deficiency
• Autoimmune disorders  (thrombocytopenia, juvenile rheumatoid arthritis, overactive thyroid)
• Seizures
• Skeletal abnormalities (extra fingers, toes, or ribs, wedge-shaped spinal bones, craniosynostosis)
• Psychiatric illness
• Eye abnormalities (ptosis, coloboma, cataract, and strabismus)
• Central nervous system abnormalities

Developmental delay, intellectual disability, and learning differences are also common in individuals with 22q11.2 deletion syndrome. Individuals may also have an autism spectrum disorders. Psychiatric illness, attention deficit disorder, anxiety, repetitive behaviors, and difficulty with social interactions are also common.

^Cause

22q11.2 deletion syndrome is caused by a missing piece (deletion) of part of chromosome 22 in each cell. The deletion occurs near the middle of the chromosome on the q arm at a location known as q11.2.

Most people with 22q11.2 deletion syndrome are missing a piece of chromosome 22 that contains about 30 to 40 genes, many of which have not been well characterized; however, some people have smaller deletions. Researchers are working to learn more about all of the genes that contribute to the features of 22q11.2 deletion syndrome. The deletion of a particular gene, TBX1, is thought to be responsible for many of the syndrome's characteristic signs and symptoms. Loss of this gene may also contribute to behavioral problems. The loss of another gene, COMT, may also cause increased risk of behavioral problems and mental illness. The other genes that are deleted likely contribute to the various features of 22q11.2 deletion syndrome.

Inheritance

Most cases of 22q11.2 deletion syndrome are not inherited from a parent and are caused by a random error during the formation of egg or sperm cells, or during early fetal development. In about 10% of cases, the deletion is inherited from a parent with the deletion.

When the deletion is inherited, it is inherited in an autosomal dominant pattern. This means that having the deletion in only one copy of chromosome 22 in each cell is enough to cause features of the condition. There is nothing that either parent can do, before or during a pregnancy, to cause a child to have this condition.
When a person with a deletion that causes an autosomal dominant condition has children, each child has a 50% (1 in 2) chance to inherit that deletion.

Treatment

The resources below provide information about treatment options for this condition. If you have questions about which treatment is right for you, talk to your healthcare professional.

Prognosis

There is a wide range of symptoms and severity among people with 22q11.2 deletion syndrome. The long-term outlook for each person depends on the specific signs and symptoms each individual has.

Factors that may impact the severity of the disease and the likelihood for a shortened lifespan include whether or not a congenital heart defect is present and how severe the defect is, as well as the severity of immune system problems. For instance, individuals with complete absence of the thymus gland and absent T cells may pass away prematurely

Data : 27/11/2017

Lo Staff / The Staff 

American Europen Medical Center 

(americaneuropeanmedicalcenter.blogspot.com) 

Direttore del sito : Daniel Viennese