How Can Down Syndrome Affect a Child's Development?

Known clinically as Trisomy 21, Down syndrome is the result of an extra copy of a chromosome, almost universally the 21st. Down syndrome will affect the development of all children born with the condition, to some degree, causing delays in learning. However, according to the Down's Syndrome Association, with early intervention and proper training, children with Down syndrome can grow up to lead productive lives.

Early Development

About 50 percent of babies born with Down syndrome will have heart defects, causing them to tire easily, according to the Down's Syndrome Association. However, many of the heart defects might be correctable through surgery. Down syndrome babies might have smaller than normal arms and hands, tend to have weak grasping strength and be either under or overweight due to thyroid issues. Compared to other children, on average, children with Down syndrome grow more slowly and commonly have significant differences in height compared to other children. Children with Down syndrome most often have delayed motor skill development, and movements such as crawling, walking, reaching and grasping will develop more slowly. Many Down syndrome children will have difficulties with math skills, learning to count and calculate. A small percentage of Down children, roughly 10 percent, will be afflicted with attention-deficit/hyperactivity disorders or one of the disorders of the autistic spectrum. On a positive note, children with Down syndrome usually exhibit strong visual learning skills and frequently excel at reading.

Vision and Hearing

According to the the Down's Syndrome Association, vision and hearing issues present frequently in children with Down syndrome. Vision issues, such a near- and far-sightedness, are common, but can usually be corrected with glasses. More serious visual issues, such as congenital cataracts that are common in Down children, can sometimes be corrected with surgery. Hearing problems are also common, but can often be mitigated with medical intervention, in the form of surgery, or managed with hearing aids and training. Because hearing and vision difficulties can affect learning if left untreated, Down syndrome children may have speech issues as well.


Many children with Down syndrome commonly experience speech delays, resulting from several causes. In addition to hearing problems causing delays in language development, problems with delayed speech can result from cognitive issues such as a weak “working,” or short-term, memory. Children with Down syndrome also frequently take longer to control the muscles used for speech, such as the lips and tongue. However, with time, most Down children are able to learn to talk normally and become effective communicators.

Thyroid Issues

According to the Down's Syndrome Association, in approximately 20 percent of children with Down syndrome the thyroid gland frequently produces abnormal levels of thyroxine, a hormone responsible for regulating and influencing development. Known as hypothyroidism, low levels of thyroxine can cause excessive weight gain, whereas with hyperthyroidism, high levels of thyroxine might result in Down children having abnormally low weight. Of the two, hypothyroidism is more prevalent in Down children. Also the result of an improperly functioning thyroid gland, “autoimmune disorder” affects roughly 30 percent of the Down population. The result of substances known as thyroid antibodies, autoimmune disorder attacks the patient’s own thyroid gland.

Gastrointestinal Problems

Children afflicted with Down syndrome often have digestive tract issues. Approximately 10 percent of Down children develop partial narrowing of the small intestine, which can restrict weight gain. Additionally, complete bowel obstruction can or part of the intestine may not form at all. In some Down children the pancreas can be malformed and abnormally positioned, causing the organ to wrap around the intestine, causing bowel obstructions. In addition to restricting weight gain, these issues often cause constant episodes of vomiting and diarrhea. If the obstruction is severe, the child will not be able to pass stools and will need surgery to correct the condition. Hirschsprung’s disease, which affects approximately 2 percent of Down children, results in missing or damaged cells in the lower part the digestive tract, limiting or preventing the passing of stool.