Practice Exam-Clinical Cytogenetics

Clinical Cytogenetics

Pdf Summary

The document contains two clinical cytogenetics practice exam questions authored by Claudia Barnett.<br /><br />The first question (ID 25221) pertains to a patient with an interstitial deletion in the proximal region of the p arm of chromosome 17, specifically a 17p11.2 deletion. The question asks what condition the patient is expected to present with. The options are:<br />- Angelman syndrome<br />- DiGeorge syndrome<br />- Neurofibromatosis 1<br />- Prader-Willi syndrome<br />- Smith-Magenis syndrome<br /><br />Based on the commentary, Smith-Magenis syndrome is associated with a 17p11.2 deletion.<br /><br />The second question (ID 25220) discusses the mechanism of action of Colcemid, which is used to halt cell division. It asks how Colcemid exerts its effect. The options are:<br />- Disrupting the centromeres of the chromosomes<br />- Disrupting the degradation of the nuclear membrane<br />- Inhibiting the formation of centrioles<br />- Inhibiting sister chromatid separation<br />- Inhibiting spindle fiber formation<br /><br />The commentary explains that Colcemid is a mitotic spindle poison that interferes with the formation and assembly of the mitotic spindle during mitosis and meiosis. Therefore, the correct answer is inhibiting spindle fiber formation.<br /><br />The document also makes references to several genetic disorders: Prader-Willi Syndrome (PWS) and Angelman Syndrome (AS) are often associated with microdeletions in the 15q11.2-q13.1 region. DiGeorge syndrome is associated with a 22q11.2 microdeletion, and Neurofibromatosis 1 can occur due to a 17q11.2 microdeletion spanning the NF1 gene.

Keywords

clinical cytogenetics

Smith-Magenis syndrome

17p11.2 deletion

Colcemid

mitotic spindle

chromosome 17

Angelman syndrome

Prader-Willi syndrome

DiGeorge syndrome

Neurofibromatosis 1