As shown in the genogram diagram below, Down syndrome is caused by trisomy 21 — the person has three copies of chromosome 21, instead of the usual two copies, in all cells. This is caused by abnormal cell division during the sperm cell or the egg cell development. As multiple research suggests, a common symptom of Down syndrome is low muscle tone which causes a greater amount of fat mass and less muscle mass. This increased fat mass, along with a higher prevalence of obesity, puts the Down syndrome population at a greater risk for type 2 diabetes and cardiovascular disease. While creating a down syndrome genogram, you can consider including both the paternal and maternal side of the child, ensuring the exact medical history of the family.
