Down syndrome is caused by abnormalities in a baby’s DNA. Normally, a person has 46 chromosomes. But most people with Down syndrome have 47 chromosomes. In rare cases, other chromosome problems cause Down syndrome. Having extra or abnormal chromosomes changes the way the brain and body develop.
Maternal age is the only factor that has been linked to an increased chance of having a child with Down syndrome. The risk increase with the mother’s age at pregnancy.
• 1:385 risk at 35 years
• 1:106 at 40 years
• 1:30 at 45 year
The risk also increases after a previously affected pregnancy :
• With regular trisomy 21, the recurrence risk is 0.75% at 12 weeks; 0.42% during the middle trimester and 0.34% at term.
• Following trisomy due to a translocation, the recurrence risk is dependent on the type of translocation and which partner carries the translocation.
• People with Down's syndrome rarely have children. Of maternal offspring, less than half have Down's syndrome.
The prognosis for people with Down's syndrome depends on the nature and severity of any associated condition. Life expectancy is improving, especially because of improved diagnosis and management of those people with Down's syndrome who also have congenital heart defects.At least half of people with Down's syndrome now live into their 50s and 60s.
Treatment for Down syndrome focuses on making sure that your child has regular medical checkups, watching for early signs of health problems, and finding support. Children with Down syndrome do learn and are capable of developing skills throughout their lives. They just follow a different pace in achieving their unique set of skills and abilities.
Typically a doctor would evaluate the child and prescribe therapies based on their needs. These may include special educators, speech therapy, occupational therapy, physical therapy.
Research indicates that early intervention improves outcome for children with Down syndrome. This assistance can begin shortly after birth and often continues until a child reaches age 3.
It is one of the most common genetic disorders, affecting 1 in 650-1,000 children.
• The underlying genetic defect is trisomy 21 in 94% of cases.
• Mosaicism (2.4%) and translocations (3.3%) also occur.
• 75% of these translocations are de novo errors.