Peripheral blood G-band karyotype analysis is typically requested for which of the following reasons?

Peripheral blood G-band karyotype analysis is primarily utilized to identify chromosomal abnormalities that may be linked to various genetic conditions. In cases where there is mental retardation of unknown etiology, karyotyping serves as a crucial tool for investigating potential underlying genetic causes. This analysis allows for the detection of structural abnormalities (such as translocations, deletions, or duplications of chromosomal regions) and numerical abnormalities (such as aneuploidies) that may contribute to cognitive impairments.

When examining individuals with intellectual disabilities or developmental delays, identifying any chromosomal anomalies can provide insight into the diagnosis and help in understanding the patient's condition, guiding management and providing reproductive counseling to families. Thus, the use of G-band karyotype analysis in this context is well established and has the potential to uncover genetic syndromes previously unrecognized that could explain the patient’s symptoms.