Down syndrome, also called trisomy 21, is a genetic disorder in which a child is born with a partial or complete extra copy of chromosome 21. This additional genetic material causes specific physical characteristics and developmental delays.
Most children with Down syndrome may face physical, mental, and behavioral issues. However, early diagnosis and treatment can significantly improve their quality of life.
Read this post to know more about the signs, symptoms, types, causes, risk factors, diagnosis, and treatment options for Down syndrome in children.
Signs And Symptoms Of Down Syndrome
The signs and symptoms of Down syndrome may vary among children. While some children with Down syndrome can be healthy, others might have severe issues, such as heart defects. Also, the severity of intellectual and developmental problems in children with Down syndrome may vary.
- Small head
- Short neck
- Flat face
- Protruded tongue
- Upward slanting eyes
- Poor muscle tone
- Increased flexibility in the joints
- Tiny feet and hands with short fingers
- Small or unusually shaped ear
- Brushfeild spots (white spots on the iris)
- Short height compared with their peers
- Mild to moderate cognitive impairment
- Delayed language and speech development
- Memory problems
Types Of Down Syndrome
Down syndrome can be of three types based on the following three genetic variations (3):
- Trisomy 21: This is the most common genetic variation seen in children with Down syndrome. In this condition, three copies of chromosome 21 are present in all cells instead of the usual two copies. Abnormal cell division during egg or sperm development can be responsible for this.
- Mosaic Down syndrome: This is a rare form in which an extra copy of chromosome 21 is present in some cells.
- Translocation Down syndrome: In this type of Down syndrome, an extra part or a whole copy of chromosome 21 is attached to another chromosome instead of being separate.
Causes Of Down Syndrome
Humans normally have 23 pairs of chromosomes, with one chromosome in each pair from both parents (4). The presence of a full or partial extra chromosome 21 material due to abnormal cell division causes Down syndrome in most children.
Chromosomal abnormalities can occur at random events during egg or sperm formation or fertilization. There is no evidence of environmental factors or behavioral factors of parents causing Down syndrome (5).
Although most cases of down syndrome are not inherited, in some rare cases, translocation Down syndrome can be passed on from a parent to the child (4).
Risk Factors For Down Syndrome
The following factors may increase your risk of having a baby with Down syndrome (6):
- Advanced maternal age: Your risk of having a baby with Down syndrome may increase with age since older ovum (egg) has more risk for abnormal chromosome division. Usually, the risk increases after 35 years of age. However, babies with Down syndrome are also born to mothers younger than 35.
- Carrier of genetic translocation for Down syndrome: Although rare, a child may develop Down syndrome if any of the parents passes the genetic translocation to them.
- Siblings with Down syndrome: Parents who have a child with Down syndrome, and parents who have a translocation themselves are at an increased risk of having another child with Down syndrome.
Parents are advised to seek a genetic counselor’s advice if they have an increased risk for having a second child with Down syndrome.
Complications Of Down Syndrome
- Heart defects: About 50% of children with Down syndrome are born with life-threatening congenital heart defects requiring surgery in early infancy.
- Immune disorders: Children with Down syndrome are more likely to develop autoimmune disorders, cancers such as leukemia, and infectious diseases such as pneumonia due to immune abnormalities.
- Gastrointestinal (GI) defects: Down syndrome may increase the risk of abnormalities of the intestines, esophagus, and anus. These may often result in GI blockage, acid reflux (heartburn), and celiac disease in some children.
- Spinal issues: Misalignment of the first two vertebrae, often called atlantoaxial instability, is seen in some children with Down syndrome. This may cause injury to the spinal cord if the neck is overextended.
- Obesity: There is an increased risk of obesity in children with Down syndrome.
- Sleep apnea: Changes in soft tissues and skeletal system may contribute to airway obstruction in some children with Down syndrome.
- Dementia: Down syndrome may increase one’s risk of developing Alzheimer’s disease in the 50s, and Alzheimer’s disease may contribute to dementia.
- Dental issues: Children with Down syndrome are at an increased risk of having Teeth damages and gum diseases.
- Seizures: The risk for seizures is higher in children with Down syndrome than in the general population. This can be due to the reduced inhibition of electrical pathways in the brain.
- Endocrine abnormalities: Children with Down syndrome are also at a higher risk of having endocrine abnormalities, with hypothyroidism being the most common one.
- Vision problems: Visual acuity issues may also be seen in children with Down syndrome, and they may require corrective glasses from a very young age.
- Ear infections and hearing issues: Facial anatomy and upper respiratory tract infections may often contribute to ear infections in children with Down syndrome. Infections may also cause conductive hearing loss.
The complications may occur or worsen with advancing age. Regular follow-up is recommended to identify and treat the complications before they worsen.
When To See A Doctor?
Down syndrome is usually diagnosed before birth or at birth. Pediatricians may plan the follow-ups depending on the severity of the child’s condition. Children with coexisting issues, such as heart problems, may require more frequent visits and procedures than those with milder cases.
Talk to your child’s pediatrician to know the individualized plan of care. Early training and treatments may help improve the quality of life in most children with Down syndrome.
Diagnosis Of Down Syndrome
The American College of Obstetricians and Gynecologists recommends all pregnant women undergo screening and diagnosis for Down syndrome during pregnancy regardless of age. Newborns may also be screened for Down syndrome if required. Diagnostic and screening tests for Down syndrome may include (2) (8):
1. Screening tests during pregnancy
Screening tests predict the likelihood of a mother carrying a baby with Down syndrome during pregnancy. These tests are often offered as part of routine prenatal care and help identify the need for more specific diagnostic tests.
First trimester combined test and integrated screening test are common screening tests for Down syndrome during pregnancy. The first trimester combined test is done in two steps, and the result, along with maternal age, helps establish the possible diagnosis. The two steps include:
- Blood test: This helps determine the levels of the pregnancy hormone human chorionic gonadotropin (HCG) and pregnancy-associated plasma protein-A (PAPP-A). Abnormal levels may indicate problems in the fetus.
- Nuchal translucency test: This test entails using ultrasound to measure specific areas on the back of the fetal neck. Increased fluid in the neck area may indicate fetal abnormalities.
The integrated screening test combines the test results in the first and second trimester of pregnancy. Blood levels of four pregnancy-associated substances, namely alpha fetoprotein, estriol, HCG, and inhibin A, in the second trimester (known as the quad screen) may help identify the possibility of Down syndrome.
Usually, second-trimester screening tests are recommended for suspected cases from the initial screening tests.
2. Diagnostic tests during pregnancy
The following diagnostic tests during pregnancy are recommended for women with positive screening test results.
- Chorionic villus sampling (CVS): This test analyzes fetal chromosomes on cells collected from the placenta. It is usually done between 10 and 13 weeks of gestation and poses a low risk for pregnancy loss (miscarriage).
- Amniocentesis: This test is done to analyze fetal chromosomes in the amniotic fluid sample collected from around the fetus using a needle. It is performed after 15 weeks of gestation and carries a low risk of miscarriage.
- Cordocentesis: Also called percutaneous umbilical blood sampling, this involves collecting fetal chromosomes from the umbilical cord for testing.
3. Preimplantation genetic testing
Preimplantation genetic diagnosis is made through in vitro fertilization (IVF), primarily if the parents have known risk factors. The embryo is tested for genetic abnormalities before it is implanted in the womb. Only healthy embryos are implanted into the uterus in IVF.
4. Diagnostic tests in newborns
Physical features are often examined to help diagnose Down syndrome in newborns. However, it is essential to do genetic testing since these features are also seen in children without Down syndrome. Your doctor could likely order a test called chromosomal karyotyping, in which a sample of your child’s blood is tested to analyze your child’s chromosomes.
Treatment For Down Syndrome
There is no specific cure for Down syndrome. However, early diagnosis and treatments may improve the quality of life in most children. Early interventions, including specialized programs and resources, are beneficial. Treatment options are planned based on the individual requirements. Doctors from various specialties are involved in Down syndrome care since multiple anomalies are often seen.
The common treatments for Down syndrome include (9):
- Surgeries for cardiac defects and gastrointestinal anomalies.
- Physical therapy, such as activities and exercises. This may help increase muscle strength, improve balance and posture, and build motor skills.
- Speech and language therapy. This may help with speech and language development.
- Occupational therapy. This may help your child develop self-care skills such as dressing up, using a computer, and writing.
- Behavioral and emotional therapies. These may help your child deal with their emotions.
- Drugs and supplements such as psychoactive drugs and amino acid supplements. These may be prescribed depending on the symptoms.
- Assistive devices. These are often recommended to help improve the child’s quality of life.
Advanced medical care and follow-ups play a role in increasing life expectancy in children with Down syndrome. If managed well, depending on the severity of the condition, a person with Down syndrome can live more than 60 years. You may discuss with the pediatrician to know the exact prognosis based on individual factors.
Can Down Syndrome Be Prevented?
Down syndrome is not a preventable condition. Genetic counseling is recommended for parents with an increased risk of having a child with Down syndrome. A genetic counselor may help identify your risk of having a baby with Down syndrome and suggest prenatal diagnostic tests (7).
Seeking support from friends, family, and support groups can be beneficial if you have a child with Down syndrome. Educate yourself about the condition and keep encouraging your child to improve their quality of life. With proper support and resources, most people with Down syndrome can live independently.
2. Down Syndrome; St. Clair Health
3. Facts About Down Syndrome; Centers for Disease Control and Prevention
4. Down Syndrome (Trisomy 21); MSD Manual
5. What Causes Down Syndrome?; Eunice Kennedy Shriver National Institute of Child Health and Human Development
6. Down Syndrome; Golisano Children’s Hospital
7. Down Syndrome (Trisomy 21) In Children; Lucile Packard Children’s Hospital, Stanford
8. What Is Down Syndrome?; National Down Syndrome Society
9. Trisomy 21 (Down Syndrome); Children’s Hospital of Philadelphia
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