22q11.2 Deletion Syndrome

22q11.2 deletion syndrome is a disorder caused by a small segment of the long arm of chromosome 22 being deleted. This condition is also known as DiGeorge syndrome, velocardiofacial syndrome, and conotruncal anomaly face syndrome.

Causes

The deletion occurs near the middle of the long arm of chromosome 22, specifically at a location labeled q11.2. The size of the deletion can vary among individuals, but it typically involves a loss of about 3 million base pairs of genetic material and includes multiple genes.

Symptoms

The symptoms of 22q11.2 deletion syndrome can vary widely in severity and impact. Common features include:

• Heart defects, particularly those affecting the outflow tracts of the heart
• Cleft palate or other abnormalities of the palate
• Characteristic facial features, such as a long face, prominent forehead, small ears, and wide-set eyes
• Learning difficulties and developmental delays
• Immunodeficiency due to thymic hypoplasia or aplasia, leading to reduced T-cell production
• Hypocalcemia (low calcium levels) due to parathyroid gland dysfunction
• Speech and feeding difficulties in infancy
• Possible psychiatric disorders, such as schizophrenia and bipolar disorder, later in life

Diagnosis

Diagnosis of 22q11.2 deletion syndrome is typically made through a combination of clinical evaluation and genetic testing. Techniques used for diagnosis include:

• FISH (fluorescence in situ hybridization), which can detect the deletion in most cases
• Microarray analysis, which can identify smaller deletions or other genetic abnormalities
• Chromosomal microarray (CMA) testing for a more detailed view of the genome

Treatment and Management

Treatment for 22q11.2 deletion syndrome is multidisciplinary, involving various medical specialties to address the wide range of potential health issues:

• Surgical interventions for heart defects and cleft palate
• Immunological management, including possible thymus transplantation or immunoglobulin replacement therapy for immunodeficiency
• Calcium and vitamin D supplementation for hypocalcemia
• Speech therapy to address communication difficulties
• Psychiatric care for any mental health issues that may arise
• Genetic counseling for families regarding the risk of recurrence in future pregnancies

Prognosis

The prognosis for individuals with 22q11.2 deletion syndrome varies depending on the severity of their symptoms and how effectively they are managed. With appropriate medical care, many people with this condition can lead active and productive lives.