Down syndrome is a genetic condition produced by an extra whole or partial copy of chromosome 21 as a result of faulty cell division. This additional genetic material is responsible for the developmental alterations and physical characteristics of Down syndrome.
Individuals with Down syndrome have varying degrees of severity, resulting in permanent intellectual impairment and developmental disabilities. It is the most frequent genetic chromosomal disease in children and the leading cause of cognitive impairments. It is also a common source of various medical problems, such as cardiac and gastrointestinal problems.
A better knowledge of Down syndrome, as well as early intervention, can significantly improve the quality of life for children and people with the disease, allowing them to live more fulfilled lives.
WHAT ARE THE SYMPTOMS OF DOWN SYNDROME?
Each person with Down syndrome is unique, with intellectual and developmental issues that can range from mild to severe. Some people are in good health, while others have substantial health issues, such as serious heart abnormalities.
Down syndrome children and adults have different face traits. Though not all persons with Down syndrome share the same characteristics, the following are some of the more prevalent ones:
- Flattened face
- Little head
- Short neck
- Tongue protruding
- Eyelids that slope upward (palpebral fissures)
- Ears that are unusually shaped or tiny
- Tiny white spots on the colored part (iris) of the eye, which are called Brushfield's spots
- Short height
- Muscle tone issues
- Hands that are broad and short, with a single wrinkle on the palm
- Short fingers, as well as tiny hands and feet
- Excessive adaptability
Infants with Down syndrome may be of ordinary size, but they often develop slowly and remain shorter than other children of their age.
Intellectual disabilities
The majority of Down syndrome children have mild to moderate cognitive impairment. Language is slowed, and both short-term and long-term memory are impacted.
WHAT ARE THE CAUSES OF DOWN SYNDROME?
Human cells typically have 23 pairs of chromosomes. Each pair contains one chromosome from your father and one from your mother.
Down syndrome is caused by faulty cell division involving chromosome 21. These defects in cell division result in an additional partial or whole chromosome 21. This additional genetic material is responsible for the distinctive traits and developmental issues associated with Down syndrome. Down syndrome can be caused by either of three genetic variations:
- Trisomy 21: Trisomy 21 causes Down syndrome 95 percent of the time, which means the person has three copies of chromosome 21 instead of the typical two copies in all cells. This is caused by aberrant cell division during the sperm or egg cell development.
- Mosaic Down syndrome: A individual with this uncommon variant of Down syndrome has only a few cells with an extra copy of chromosome 21. The aberrant cell division following conception results in this mosaic of normal and defective cells.
- Translocation Down syndrome: Before or during pregnancy, a fragment of chromosome 21 can get attached (translocated) onto another chromosome, resulting in Down syndrome. These youngsters have two copies of chromosome 21, but they also have chromosome 21 genetic material connected to another chromosome.
Down syndrome is caused by no known behavioral or environmental causes.
Is it hereditary?
Down syndrome is not usually inherited. It is caused by an error in cell division during the early stages of fetal development.
Translocation Down syndrome can be handed down from generation to generation. However, translocation affects only approximately 3 to 4% of children with Down syndrome, and only some of them acquired it from one of their parents.
When balanced translocations are inherited, the mother or father carries some rearranged genetic material from chromosome 21, but no additional genetic material. This implies he or she has no indications or symptoms of Down syndrome, but can transmit an imbalanced translocation on to offspring, resulting in Down syndrome.
WHAT ARE THE RISK FACTORS FOR DOWN SYNDROME?
Some parents are more likely to have a child with Down syndrome. The following are risk factors:
- Advancing maternal age: Because older eggs have a higher risk of incorrect chromosomal division, a woman's odds of having a kid with Down syndrome grow with age. After the age of 35, a woman's chances of having a child with Down syndrome rise. However, because younger women have considerably more kids, most infants with Down syndrome are born to women under the age of 35.
- Being carriers of the Down syndrome genetic translocation: Both men and women can pass on the Down syndrome genetic translocation to their offspring.
- Having had one child with Down syndrome: Parents who have one kid with Down syndrome and who have a translocation are more likely to have another child with Down syndrome. A genetic counselor can assist parents in determining the likelihood of having a second child with Down syndrome.
WHAT ARE THE COMPLICATIONS OF DOWN SYNDROME?
People with Down syndrome may experience a number of difficulties, some of which become more noticeable as they age. Complications may include:
- Heart problems: Approximately half of all children with Down syndrome are born with a congenital cardiac abnormality. These cardiac issues can be fatal and may necessitate surgery in infancy.
- Gastrointestinal (GI) problems: Some children with Down syndrome have GI abnormalities, which can include problems with the intestines, esophagus, trachea, and anus. The likelihood of having digestive issues such as GI obstruction, heartburn (gastroesophageal reflux), or celiac disease is raised.
- Spinal issues: Some Down syndrome patients may have a misalignment of the top two vertebrae in their neck (atlantoaxial instability). This condition puts individuals at danger of catastrophic spinal cord damage from neck overextension.
- Leukemia: Young children with Down syndrome are more likely to get leukemia.
- Dementia: People with Down syndrome are at a much higher risk of developing dementia; indications and symptoms may appear around the age of 50. Down syndrome also raises the likelihood of acquiring Alzheimer's disease.
- Immune disorders: People with Down syndrome are more likely to develop autoimmune illnesses, some types of cancer, and infectious diseases such as pneumonia due to immune system abnormalities.
- Sleep apnea: Children and adults with Down syndrome are at a higher risk of obstructive sleep apnea due to soft tissue and skeletal abnormalities that create airway blockage.
- Obesity: Obesity is more common in people with Down syndrome than in the general population.
- Other issues: Other health concerns that may be connected with Down syndrome include endocrine disorders, dental problems, seizures, ear infections, and hearing and vision impairments.
Getting routine medical care and managing difficulties as they arise can help persons with Down syndrome maintain a healthy lifestyle.
Life expectancy
People with Down syndrome are living longer lives than ever before. People with Down syndrome can now expect to live for more than 60 years, depending on the severity of their health problems.
HOW IS DOWN SYNDROME DIAGNOSED?
The American College of Obstetricians and Gynecologists advises that all pregnant women, regardless of age, be given the choice of screening and diagnostic testing for Down syndrome.
- Screening tests can show whether or not a mother is carrying a child with Down syndrome. However, these tests cannot determine or diagnose if the newborn has Down syndrome.
- Diagnostic testing can determine whether or not your baby has Down syndrome.
Your doctor may go through the many types of testing, the pros and downsides, the benefits and dangers, and the significance of your results with you. If necessary, your provider may advise you to consult with a genetics counselor.
Screening tests during pregnancy
Prenatal treatment includes a standard screening for Down syndrome. Although screening tests can only detect your risk of having a child with Down syndrome, they can assist you in making decisions regarding more specialized diagnostic testing.
The first trimester combination test and the integrated screening test are examples of screening tests.
The first trimester combined test
The first trimester combination test is performed in two phases and includes:
- Blood test: This blood test evaluates the levels of pregnancy-associated plasma protein-A (PAPP-A) and human chorionic gonadotropin (HCG) (HCG). PAPP-A and HCG levels that are abnormal may suggest an issue with the fetus.
- Nuchal translucency test: An ultrasound is performed during this exam to measure a specific spot on the back of your baby's neck. A nuchal translucency screening test is used for this. When there are anomalies, this neck tissue tends to accumulate more fluid than usual.
Your doctor or genetic counselor can estimate your chance of having a baby with Down syndrome based on your age and the results of the blood test and ultrasound.
Integrated screening test
During the first and second trimesters of pregnancy, the integrated screening test is administered in two sections. The data are pooled to determine your baby's chances of having Down syndrome.
- The first trimester: Part one consists of a blood test to determine PAPP-A levels and an ultrasound to determine nuchal translucency.
- The second trimester: The quad screen detects four pregnancy-related chemicals in your blood: alpha fetoprotein, estriol, HCG, and inhibin A.
Diagnostic tests during pregnancy
If the findings of your screening tests are positive or concerning, or if you are at high risk of having a baby with Down syndrome, you should seek further testing to confirm the diagnosis. Your doctor can assist you in weighing the benefits and drawbacks of these tests.
Among the diagnostic tests that can detect Down syndrome are:
- Chorionic villus sampling (CVS): CVS involves extracting cells from the placenta and analyzing the fetal chromosomes. This test is usually done between 10 and 13 weeks of pregnancy, during the first trimester. A CVS has a very low chance of pregnancy loss (miscarriage).
- Amniocentesis: A sample of the amniotic fluid around the fetus is obtained by inserting a needle into the mother's uterus. This sample is then utilized to examine the fetus's chromosomes. Doctors commonly do this test after 15 weeks of pregnancy, in the second trimester. This test is also associated with a very low risk of miscarriage.
Preimplantation genetic diagnosis is an alternative for couples who are at high risk of passing on specific genetic abnormalities during in vitro fertilization. Before being placed in the womb, the embryo is checked for genetic abnormalities.
Newborn diagnostic tests
The look of the newborn is frequently used to make the initial diagnosis of Down syndrome after birth. However, because the characteristics associated with Down syndrome can be detected in newborns without Down syndrome, your doctor will most likely request a test called a chromosomal karyotype to confirm the diagnosis. This test examines your child's chromosomes using a blood sample. Down syndrome is diagnosed when there is an extra chromosome 21 in all or some cells.
WHAT ARE THE TREATMENTS FOR DOWN SYNDROME?
Early intervention for newborns and children with Down syndrome can significantly improve their quality of life. Because each kid with Down syndrome is unique, therapy will be tailored to their specific need. Furthermore, different periods of life may necessitate different services.
Team care
If your kid has Down syndrome, you will most likely rely on a team of professionals to offer medical treatment and assist him or her in developing abilities to the greatest extent feasible. Your team may comprise some of the following professionals, depending on your child's specific needs:
- Primary care pediatrician to coordinate as well as provide routine childhood care
- Pediatric cardiologist
- Pediatric gastroenterologist
- Pediatric endocrinologist
- Pediatric neurologist
- Pediatric ear, nose and throat (ENT) specialist
- Pediatric eye doctor (ophthalmologist)
- Developmental pediatrician
- Audiologist
- Speech pathologist
- Physical therapist
- Occupational therapist
You will have to make significant decisions regarding your child's health and education. Create a trusted team of health care providers, teachers, and therapists. These individuals can assist you in evaluating local resources and explaining state and federal programs for children and adults with disabilities.
HOW CAN DOWN SYNDROME BE PREVENTED?
There is no way to avoid being born with Down syndrome. If you are at high risk of having a child with Down syndrome or already have one, you should visit a genetic counselor before becoming pregnant.
A genetic counselor can assist you in determining your risk of having a child with Down syndrome. He or she can also discuss the many prenatal tests available and the benefits and drawbacks of testing.