Microdeletion syndrome

Children with 22q11.2 microdeletion syndrome

Microdeletion syndrome refers to a group of genetic disorders caused by the deletion of a small segment of a chromosome. These deletions are typically too small to be detected by conventional karyotyping and often require more sensitive techniques such as fluorescence in situ hybridization (FISH) or comparative genomic hybridization (CGH) for diagnosis.

Characteristics

Microdeletion syndromes can result in a wide range of clinical features, depending on the specific genes that are deleted. Common characteristics may include developmental delays, intellectual disabilities, distinctive facial features, and congenital anomalies. The severity and specific symptoms can vary widely even among individuals with the same microdeletion.

Common Microdeletion Syndromes

22q11.2 Deletion Syndrome

The 22q11.2 deletion syndrome, also known as DiGeorge syndrome or velocardiofacial syndrome, is one of the most common microdeletion syndromes. It is caused by the deletion of a small segment of chromosome 22 and can lead to heart defects, immune deficiencies, and characteristic facial features.

Williams Syndrome

Williams syndrome is caused by a deletion on chromosome 7q11.23. It is characterized by cardiovascular disease, distinctive facial features, and a unique cognitive profile with strengths in verbal short-term memory and language.

Prader-Willi Syndrome

Prader-Willi syndrome is associated with a deletion on chromosome 15q11-q13. It is characterized by hypotonia, obesity, intellectual disability, and hypogonadism.

Angelman Syndrome

Angelman syndrome results from a deletion on chromosome 15q11-q13, similar to Prader-Willi syndrome, but involves different genes. It is characterized by severe intellectual disability, lack of speech, and a happy demeanor.

Diagnosis

Diagnosis of microdeletion syndromes often involves genetic testing techniques such as FISH, CGH, or next-generation sequencing. These tests can identify the specific chromosomal deletions responsible for the syndrome.

Management

Management of microdeletion syndromes is typically multidisciplinary, involving specialists in genetics, cardiology, neurology, and other fields as needed. Treatment focuses on addressing the specific symptoms and complications associated with the syndrome.

Related Pages

• Chromosomal deletion
• Genetic disorder
• Fluorescence in situ hybridization
• Comparative genomic hybridization