The most common reason a physician might recommend that a woman have maternal serum screening and a karyotype analysis is concern that her fetus may have Down syndrome. Go to the OMIM website at www.ncbi.nlm.nih.gov/omim and look up Down syndrome (OMIM 190685).

Summarize what is known about the location and genes found within the DSCR.

Key Concepts

Down Syndrome

Down syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of an extra copy of chromosome 21. This condition leads to developmental delays, characteristic physical features, and an increased risk of certain health issues. Understanding the genetic basis of Down syndrome is crucial for recognizing its implications and the importance of genetic screening.

DSCR (Down Syndrome Critical Region)

The Down Syndrome Critical Region (DSCR) is a segment of chromosome 21 that is believed to contain genes that contribute to the phenotypic features of Down syndrome. Research indicates that specific genes within this region may be responsible for the cognitive and physical characteristics associated with the disorder. Identifying these genes helps in understanding the biological mechanisms underlying Down syndrome.

Karyotype Analysis

Karyotype analysis is a laboratory technique used to visualize an individual's chromosomes to assess their number and structure. This analysis is essential for diagnosing chromosomal abnormalities, such as Down syndrome, by identifying the presence of an extra chromosome 21. It provides critical information for genetic counseling and management of the condition.