Down syndrome, also called Trisomy 21 is a genetic disorder which is a result of an error in cell division that results in an extra 21st chromosome. This extra chromosome causes mental and physical developmental delays.
Causes
An abnormality in cell division in the early embryo development results in Down syndrome. Normally, 23 chromosomes from each parent are inherited to a child. A fetus with Down syndrome has extra or abnormal chromosomes. The way of developing the brain and body is due to the extra genetic material. The type of Down syndrome depends on how many cells have the extra or abnormal chromosomes.
Characteristics of Down syndrome
Individuals with Down syndrome often have unique health issues, distinct physical characteristics, and variability in cognitive development.
Common Physical signs of Down syndrome include:
Low muscle tone at birth
Small stature and short neck
Flattened nose, small ears and small mouth
Single crease in the palm of the hand
White spot on the colored part of the eye
Protruding tongue
Separated joints between the bones of the skull
Children with Down syndrome often have a speech delay and require speech therapy for an expressive language. In addition, fine motor skills are delayed and tend to lag behind gross motor skills. Also, they may not walk until age 4, but some will walk at the age of only 2.
Individuals with Down syndrome can have abnormalities affecting general health that may affect any organ system or bodily function. They have an increased risk for congenital heart defects, respiratory and hearing problems, Alzheimer’s disease, childhood leukemia, epilepsy, and thyroid conditions. However, people with Down syndrome also have a lower risk of hardening of the arteries, diabetic retinopathy, and most kinds of cancer.
Symptoms
There are more than 50 features of Down syndrome. The features or health problems with Down syndrome varies from one person to another. Some features and problems are common.