Down syndrome: Nursing

Down syndrome is a chromosomal abnormality caused by a genetic mutation leading to an extra or partial copy of chromosome 21.

Now, chromosomes are molecules that carry packaged DNA information for a person, like a storage bin. Every cell in our body has 46 chromosomes, organized into 23 pairs. During human fertilization, each parent donates half of their chromosomes to create a zygote with a total of 46 chromosomes. But in some cases, like in Down syndrome, one parent donates an extra chromosome, leaving the zygote with 47 chromosomes. People with Down syndrome receive an extra copy of chromosome 21, which is why Down syndrome is also referred to as Trisomy 21, or “three chromosome 21s."

The exact cause of Down syndrome is unknown. What we do know is that the likelihood of Down syndrome increases with the age of the mother. So, a 35-year-old mother is more likely to give birth to a baby with Down syndrome than a 25-year-old mother. Down syndrome also seems to arise more often from patients who have translocation of chromosomes 15, 21, or 22, where parts of one chromosome switch places with another chromosome, creating an atypical hybrid of the two original chromosomes. This is referred to as Robertsonian translocation.

Down syndrome has a number of clinical manifestations. Several changes to the face occur. Skin folds covering the inner corner of the eyes develop, called inner epicanthal folds, along with an upward slant in the palpebral fissure. A depressed nasal bridge or flattening of the top part of the nose may also develop along with a protruding tongue. Speckling of the iris, known as Brushfield spots, might also appear. People with Down syndrome may also have small ears with narrow canals.

Other clinical manifestations include a shortened rib cage, umbilical hernia, and protruding or loose abdominal muscles. People with Down syndrome typically have short stature, hyper-flexibility with muscle weakness, and atlantoaxial instability, or excessive movement between cervical vertebrae. They also may have transverse palmar crease, or a single line that runs across the palm of the hand.

People with Down syndrome are at an increased risk of developing a number of medical conditions. They may be born with a congenital heart defect, like a ventricular septal defect, and they are more likely to develop hypothyroidism as well as blood cancers such as acute lymphoblastic leukemia. They’re also at a higher risk of developing vision and hearing problems. Developmental and cognitive impairments may also occur, with many patients having learning difficulties, and some developing early onset dementia.