Question

Describe the pathogenesis of Chromosome 22q11.2 Deletion Syndrome.

Answer 1

Chromosome 22q11.2 Deletion Syndrome is caused by the loss of a segment on chromosome 22, leading to missing crucial genes and resulting in various developmental issues affecting multiple body systems.

Step-by-step explanation:

Pathogenesis of Chromosome 22q11.2 Deletion Syndrome

Chromosome 22q11.2 Deletion Syndrome is characterized by the loss of a small segment of chromosome 22 known as 22q11.2. This deletion results in a range of developmental issues and can affect multiple body systems. The pathogenesis of this syndrome involves the absence of genes located in the deleted region, which are crucial for normal development and function. These missing genes can lead to diverse clinical manifestations, including heart defects, immune deficiencies, cleft palate, and developmental delays. The degree of severity can vary widely, owing to factors such as the exact size of the deletion and the specific genes that are affected.

Cytologists have recognized that structural chromosomal rearrangements, like deletions, can lead to offspring that survive but display physical and mental abnormalities. An example provided for such structural changes is Cri-du-chat syndrome, which presents nervous system abnormalities and is also due to a chromosomal deletion. While Chromosome 22q11.2 Deletion Syndrome differs from Cri-du-chat, they both exemplify how lost chromosomal material can disrupt normal development and function.

Down syndrome is another chromosomal disorder that highlights the effects of abnormal chromosomal numbers or structures, in this case, trisomy 21 - an extra chromosome 21. However, the 22q11.2 deletion is a microdeletion syndrome, which means that only a tiny portion of a chromosome is missing, but still leads to significant health implications for individuals.

Answer 2

Chromosome 22q11.2 Deletion Syndrome is caused by a deletion of genetic material on chromosome 22, affecting development and resulting in various health issues. This syndrome exemplifies how chromosomal abnormalities during meiosis can lead to genetic disorders with physical and mental manifestations.

Step-by-step explanation:

The student has asked about the pathogenesis of Chromosome 22q11.2 Deletion Syndrome. Chromosome 22q11.2 Deletion Syndrome, also known as DiGeorge syndrome, is a disorder caused by a deletion of a small piece of chromosome 22. This missing genetic material leads to developmental issues and a variety of both physical and mental health problems. During the process of meiosis, when reproductive cells divide to form sperm and eggs, chromosomes are supposed to segregate equally. However, errors can occur, such as deletions or duplications of chromosome segments, which can then be passed on to offspring. A deletion in chromosomal region 22q11.2 may result in this syndrome.

Symptoms and characteristics can include heart defects, cleft palate, distinctive facial features, and immune system issues, all resulting from the loss of genetic material necessary for normal development of various body systems. Affected individuals also often have developmental and learning delays or difficulties, emphasizing the importance of the affected chromosomal region in neurological development.In comparison, other chromosomal disorders mentioned in the reference material, such as Cri-du-chat syndrome, are caused by deletions on other chromosomes (e.g., chromosome 5) and Down syndrome by trisomy 21, where an individual has an extra copy of chromosome 21.