Down syndrome is a genetic disorder that is caused when an abnormal cell division leads to the generation of extra genetic material from a chromosome. Normally, a person has 46 chromosomes, but people with down syndrome have an extra copy of chromosome number 21. This additional chromosome leads to several developmental and cognitive challenges among patients with Down syndrome.
Also known as Trisomy 21, this disorder is one of the most prevalent genetic birth diseases among children, affecting around 1 in every 830 live births. In India, every year, approximately 1.3 lakh children are born with this condition. Despite these worrying statistics, due to the lack of information and discussion, many children continue to suffer from this condition.
What are the factors that can cause down syndrome?
While it is known that extra chromosome 21 can lead to down syndrome, the exact cause of this chromosomal abnormality remains unknown. A woman's age during childbirth is also another factor that often increases the risk of having a child with Down syndrome. Women who are older than 35 years of age are found to be more prone to having a child with Down syndrome when compared with women of a lower age group.
How many types of Down syndrome are there?
Three types of Down syndrome have been detected to date. These include -
Trisomy 21: It is a type of down syndrome that has three separate copies of chromosome 21 instead of two.
Translocation Down syndrome: This type of down syndrome occurs when an extra chromosome 21 attaches to a different chromosome.
Mosaic Down syndrome: It is a mixture of some cells with normal set of (two) chromosome 21 and some cells have three copies of chromosome 21.
What are the different types of tests that are available to detect Down syndrome?
With the advancements in technology and laboratory testing, Down syndrome can be detected in up to 90% of cases. Women in the early stages of their pregnancy can undergo the following tests to detect if their child s being born with Down syndrome -
Fetal ultrasound to look for clinical signs in fetus and blood markers to detect risk of carrying a child with Trisomy 21
Genetic Testing - It is one of the most effective ways to predict a child’s future and understand if they are suffering from any other congenital disorder. Women who have had several abortions can undergo genetic testing to monitor their child’s development regularly.
Screening Tests - Couples who are looking to get married or want to conceive can undergo screening tests to check if their child will be at risk of any inherited or genetic ailment.
What are the precautions that parents can take after conception?
Once a baby is born, parents must undertake certain evaluations to help the baby have a better health outcome. Below are some tips that parents can follow to help their children -
Heart defects (50%): There is a 50% risk of a child being born with a structural heart defect. Hence, an ECHO should be done irrespective of fetal scans to rule out any abnormalities.
Gastrointestinal problems: These are extremely common issues among newborns. Several newborns often have difficulty digesting food and often require a tube to feed. If your child is having constipation or rarely obstruction in the gut (Atresia), then he/she will need a surgeon's help to relieve the obstruction.
Hearing Loss: Many children are prone to congenital hearing loss, which needs to be detected and acted upon for improving their hearing and speech development. A child should undergo an OAE before discharge from the hospital and a BERA by 3 months of age to analyze their hearing function. In case there are any abnormal symptoms in the child then the baby needs to be closely followed up.
Hypothyroidism: Children are at a high risk of hypothyroidism and so checking their thyroid function is of utmost importance.
Other problems: Children can have issues like apnoea (temporary cessation of breathing), Cataract, and thick blood (polycythemia), which needs to be checked and addressed accordingly. It is recommended that a child should have had a BERA (hearing test), and visual evaluation by three months of age.
Apart from these tests, a child should be evaluated for developmental milestones including social communication skills, weight, height, sleep including any symptoms of snoring/sleep apnoea.
Children with Down syndrome are also at risk of atlantoaxial subluxation, meaning instability between 1st and 2nd cervical bones, hence they need to be monitored after 3 years of age, and they should avoid trampoline use. As they are growing, they are prone to obesity, sleep disorders, and coeliac disease, which need to be evaluated by asking parents about the symptoms of these diseases and also undertaking relevant tests such as an annual thyroid function test to help them achieve a healthy weight.
How can parents help their children lead normal life?
In summary, children with Down syndrome can undergo a normal course in life with the least problems and with regular monitoring and follow-up. Parents can use this basic checklist to help their child avoid any complications -
Cardiac: ECHO and cardiac review at birth and subsequently to keep a tab on your child’s heart function
Breathing, snoring and recurrent ear infection: You should regularly monitor these issues and should reach out to a doctor in case there are any concerning factors.
Development: Parents must keep an eye on motor delay and social skill development and should monitor their child’s milestones. A regular follow-up with the doctor is strongly recommended to track the progress of the child.
Intellectual disability and social development: It is a moderate risk, which needs to be monitored at each visit to a paediatrician.
Blood test: Annually as a minimum to check thyroid function, more frequently if required. As children with Down Syndrome are at a higher risk of blood disorders such as leukaemia, therefore, blood tests are critical.
Gut issues: Any gut issue, coeliac screening and follow-up with a paediatrician or gastroenterologist will help with early management.
With these steps, parents of children with down syndrome can be more informed and can empower their children to lead normal life.
Authored by Dr Gowri Chinthalapalli, Consultant - Developmental Medicine, MRCGP (U.K.), CCT in General Practice (U.K.), Fellowship in Child Development and Disabilities, Aster CMI Hospital