The chromosomal abnormality associated with DiGeorge syndrome is a deletion on which chromosome?

The chromosomal abnormality associated with DiGeorge syndrome is a deletion on which chromosome?

• A. Chromosome 13
• B. Chromosome 22
• C. Chromosome 11
• D. Chromosome 9

Answer: (B)

DiGeorge syndrome is caused by a microdeletion on chromosome 22, specifically at the 22q11.2 region. This loss of genetic material reduces the dose of several genes, including TBX1, during development, leading to a mix of thymic hypoplasia (impaired T cell development), parathyroid aplasia (low calcium), congenital heart defects, and distinctive facial features. Because the defining genetic lesion is located on chromosome 22, that chromosome is the correct association. The other chromosomes listed are linked to different conditions, not this deletion syndrome.

DiGeorge syndrome is caused by a microdeletion on chromosome 22, specifically at the 22q11.2 region. This loss of genetic material reduces the dose of several genes, including TBX1, during development, leading to a mix of thymic hypoplasia (impaired T cell development), parathyroid aplasia (low calcium), congenital heart defects, and distinctive facial features. Because the defining genetic lesion is located on chromosome 22, that chromosome is the correct association. The other chromosomes listed are linked to different conditions, not this deletion syndrome.