Genetics for Nurses

14

Down Syndrome (Trisomy 21)

CHAPTER OBJECTIVES

• Overview
• Genetics of Down Syndrome
• Advanced Maternal Agqe in Down Syndrome
• Characteristic Features/Phenotype of Down Syndrome
• Medical Conditions Associated with Down Syndrome
• Down Syndrome Management
• Down Syndrome Diagnosis

• Down syndrome is the most common chromosomal condition affecting new born babies.
• Characteristics may include intellectual delay, distinct facial features, problems with the heart, and digestive tract.
• Down syndrome is due to one of the following:
  • An additional copy of chromosome 21 (trisomy 21) in all of the cells of the body (about 95% of cases).
  • An additional copy of chromosome 21 in some of the cells of the body (mosaic trisomy 21—about 1% of cases).
  • A chromosomal ...