The genes in the nuclei of cells in our chromosomes contain codes to all inherited traits, with each nucleus containing 23 pairs of chromosomes — half from one parent and half from the other. In Down syndrome, the nucleus contains a full or partial extra copy of chromosome 21.

  • Trisomy 21. Down syndrome or trisomy 21 has 3, rather than 2 chromosomes in a pair. With 47 total chromosomes, the extra genetic material affects brain and body development and physical traits of Down syndrome.
  • Risk Factors. Down syndrome is random, and not caused by parents’ behavior during pregnancy. Studies show individuals 35 or older are more likely to have a child with Down syndrome or another genetic condition. Roughly 6,000 babies are born with Down syndrome yearly.
  • Other Types. Translocation Down syndrome occurs when an extra part or whole extra chromosome 21 is present and attached to a different chromosome. In Mosaic Down syndrome, some cells have 2 or 3 copies of chromosome 21. Those with Mosaic Down syndrome may have fewer Down syndrome features.
  • Symptoms and Signs. Physical symptoms are present at birth and become more prominent as the baby grows, including flat nose bridge; slanted eyes pointing upward; shorter neck; small hands and feet; small pinky finger pointing inward toward thumb; weak muscle tone; palm crease; shorter-than-average height; vision or eye diseases; hearing loss or ear infections; prone to infections or illnesses; and congenital heart disease.

Children with Down syndrome may require frequent medical exams. Although Down syndrome is a lifelong condition, early intervention can help improve children’s physical and intellectual abilities.

Learn about how you can bring greater awareness of Down syndrome and support available through the Down Syndrome Parents Group of WNY at https://dspgwny.org.