Down syndrome results from having a complete or partial extra copy of chromosome 21. This extra genetic material influences the developmental process, giving rise to the characteristics linked with Down syndrome. Physical features include almond-shaped eyes, a flattened facial profile, and a shorter stature.
There are three types of Down syndrome: Trisomy 21, the most common type (95% of cases), is caused by non-disjunction. Translocation accounts for about 4%, and Mosaicism about 1%.

Down syndrome can affect individuals across various races and economic backgrounds. The likelihood of having a child with Down syndrome rises as the mother’s age increases. 

Despite this, because of higher fertility rates among younger women, 80% of children with Down syndrome are born to mothers under 35 years old. Persons with Down syndrome face an elevated risk of medical conditions, including congenital heart defects, respiratory and hearing issues, Alzheimer’s disease, childhood leukaemia and thyroid conditions.

The life expectancy for persons with Down syndrome has significantly risen in recent decades, increasing from 25 years in 1983 to 60 years today. Persons with Down syndrome now attend school, engage in the workforce, participate in decision-making processes, cultivate meaningful relationships, exercise their right to vote, and contribute to society in numerous valuable ways. 

While persons with Down syndrome may experience cognitive delays, these are generally mild to moderate and do not overshadow the many strengths and talents each person possesses.
The combination of early medical intervention and access to good healthcare, quality educational programs, a stimulating home environment and positive support from family, friends, and the community plays a crucial role in enabling persons with Down syndrome to lead fulfilling and productive lives.