Down syndrome (DS), also called Trisomy 21, is a condition in which extra genetic material causes delays in the way a child develops, both mentally and physically. It affects about 1 in every 800 babies born in the United States.
The physical features and medical problems associated with Down syndrome can vary widely from child to child. While some kids with DS need a lot of medical attention, others lead healthy lives.
Though Down syndrome can't be prevented, it can be detected before a child is born. The health problems that may go along with DS can be treated, and many resources are available to help kids and their families who are living with the condition
causes Down syndrome
Down syndrome occurs because of an abnormality characterized by an extra copy of genetic material on all or part of the 21st chromosome. Every cell in the body contains genes that are grouped along chromosomes in the cell's nucleus or center. There are normally 46 chromosomes in each cell, 23 inherited from your mother and 23 from your father. When some or all of a person's cells have an extra full or partial copy of chromosome 21, the result is Down syndrome.
The most common form of Down syndrome is known as Trisomy 21, a condition where individuals have 47 chromosomes in each cell instead of 46. This is caused by an error in cell division called nondisjunction, which leaves a sperm or egg cell with an extra copy of chromosome 21 before or at conception. Trisomy 21 accounts for 95% of Down syndrome cases, with 88% originating from nondisjunction of the mother's egg cell.
The remaining 5% of Down syndrome cases are due to conditions called mosaicism and translocation. Mosaic Down syndrome results when some cells in the body are normal while others have Trisomy 21. Robertsonian translocation occurs when part of chromosome 21 breaks off during cell division and attaches to another chromosome (usually chromosome 14). The presence of this extra part of chromosome 21 causes Down some syndrome characteristics. Although a person with a translocation may appear physically normal, he or she has a greater risk of producing a child with an extra 21st chromosome.
down syndrome symptoms
There are more than 50 features of Down syndrome. But not every person with Down syndrome has all the same features or health problems. Some features and problems are common.
Body shape and size
- Short stature (height). A child often grows slowly and is shorter than average as an adult.
- Weak muscles (hypotonia) throughout the body. Weak belly muscles also make the stomach stick out.
- A short, wide neck. The neck may have excess fat and skin.
- Short, stocky arms and legs. Some children also have a wide space between the big toe and second toe.
Face shape and features
- Slanted eyes. Tissue may also build up on the colored part of the eye (iris). But the child's vision is not affected by this buildup.
- A nasal bridge that looks pushed in. The nasal bridge is the flat area between the nose and eyes.
- Small ears. And they may be set low on the head.
- Irregularly shaped mouth and tongue. The child's tongue may partly stick out. The roof of the mouth (palate) may be narrow and high with a downward curve.
- Irregular and crooked teeth. Teeth often come in late and not in the same order that other children's teeth come in.
Health problems
Health problems related to Down syndrome, such as:
- Intellectual disability. Most children with Down syndrome have mild to moderate cognitive disability.1
- Heart defects. About half of the children who have Down syndrome are born with a heart defect.
- Hypothyroidism, celiac disease, and eye conditions.
- Respiratory infections, hearing problems, or dental problems.
- Depression or behavior problems associated with ADHD or autism.
Exams and Tests
A doctor can often make an initial diagnosis of Down syndrome at birth based on how the baby looks. The doctor may hear a heart murmur when listening to the baby's chest with a stethoscope.
A blood test can be done to check for the extra chromosome and confirm the diagnosis. See: Chromosome studies
Other tests that may be done include:
- Echocardiogram to check for heart defects (usually done soon after birth)
- ECG
- X-rays of the chest and gastrointestinal tract
- Eye exam every year during infancy
- Hearing tests every 6 - 12 months, depending on age
- Dental exams every 6 months
- X-rays of the upper or cervical spine between ages 3 - 5 years
- Pap smears and pelvic exams beginning during puberty or by age 21
- Thyroid testing every 12 months
Because it is a problem with the chromosomes, there are no cures for Down syndrome. Therefore, treatment for the condition focuses on controlling symptoms and any medical conditions that result because of Down syndrome.
Treatment for Down syndrome can include:
- Regular checkups and screening
- Medications
- Surgery
- Counseling and support.
People with Down syndrome are at increased risk for certain medical problems, such as:
- Congenital heart disease
- Leukemia and other cancers
- Immune system problems
- Thyroid problems
- Bone, muscle, nerve, or joint problems
- Hearing problems
- Eye problems
- Seizure disorders
- Developmental delay
- Mental retardation
- Premature aging
- Alzheimer's disease.
Because of these medical conditions and their associated complications, a person with Down syndrome is at increased risk of premature death. Regular checkups are important. These visits help ensure that any changes in health are noted and treated if necessary.
The doctor may also schedule certain screening tests to look for problems before symptoms occur. This is important, given the increased risk of vision and hearing problems, infections, and cancer in people with Down syndrome.
Medications can be used to treat certain conditions that occur in someone with Down syndrome. At this point, however, there is no medicine that will cure the disorder.
Some medical conditions seen in people with Down syndrome require surgery. For example, approximately half of the children with Down syndrome have congenital heart disease and associated early onset of pulmonary hypertension (high blood pressure in the lungs).
Common congenital heart problems include:
- Tetralogy of Fallot
- Persistent ductus arteriosus
- Atrial septal defect
- Ventricular septal defect.
If the heart defects have been identified before the onset of pulmonary hypertension, surgery has provided favorable results.
Furthermore, cataracts occur in approximately 3 percent of children with Down syndrome. Cataracts can generally be removed surgically (see Cataract Surgery).
Counseling for parents and people with Down syndrome at different stages of development has been shown to be beneficial. Learning as much as possible about Down syndrome and possible problems is also important. Doctors, nurses, and other members of the healthcare team can answer questions about Down syndrome treatment options.
Patients and their families often find they need help coping with the emotional and practical aspects of Down syndrome. Meeting with a social worker, counselor, or member of the clergy can be helpful for those who want to talk about their feelings or discuss their concerns.
Down syndrome support groups can also help. In support groups, patients and their family members get together to share what they have learned about coping with the disease. People with Down syndrome may want to talk with a member of their healthcare team about finding a support group. These groups can offer support in person, over the telephone, or on the Internet.
ليست هناك تعليقات:
إرسال تعليق