เลือกหัวข้อที่อ่าน

• What causes Down syndrome?
• What are the symptoms of Down syndrome?
• How is Down syndrome screening before birth?
• How is Down syndrome diagnosed after birth?
• How is Down syndrome treated?
• What is the prevention of Down syndrome?

Down Syndrome

Down syndrome is a genetic disorder caused by an extra full or partial cell division of a human’s chromosome 21, resulting in lifelong intellectual disability, delayed development, a unique body and face, and abnormalities in various body systems. All unborn children and mothers are at risk of Down syndrome. Therefore, pregnant women should have the Down's syndrome screening test or the NIPT test. A newborn baby diagnosed with Down syndrome should be closely treated and monitored by a specialist doctor in order to plan systematically for the baby's future.

What causes Down syndrome?

The main cause of Down syndrome is an abnormal division (non-disjunction) of the pair of chromosomes 21 (trisomy 21) during meiosis, which divides an extra chromosome in every cell of the body. There is no other cause for Down syndrome, such as behavior or environment. Typically, human chromosomes consist of 23 pairs of chromosomes, totaling 46 chromosomes, with each pair of chromosomes consisting of 1 chromosome from the father and 1 chromosome from the mother (22+xy = 23 for males and 22+xx = 23 for females).

Chromosomes contain genetic material, or DNA, that controls genetic traits that are passed down from parent to child, such as height, skin color, eye color, hairstyle, or physical appearance. An abnormal division increases the number of chromosomes from 46 to 47, resulting in various abnormalities in the fetus's body system in the mother's womb. The causes of Down syndrome are as follows:

• Trisomy 21: Having one extra pair of chromosomes 21 in every cell of the body, caused by an abnormality in chromosome division in sperm or egg cells during the conception of the fetus in the mother's womb, which is the main cause found in up to 95% of all Down syndrome causes.
• Translocation Down syndrome is caused by a part or one of the other pairs of chromosomes breaking off while creating reproductive cells and causing shifted movement to change the position of that chromosome with the 21 (Robertsonian translocation), resulting in an excess of the 21.
• Mosaic Down syndrome is characterized by the presence of an unequal number of chromosomes in some cells (2 cell lines), including both normal 46 and abnormal 47 chromosomes in the same body, particularly in Down syndrome infants, who frequently find an extra chromosome 21. This is an abnormality in the division of chromosomes in cells after fertilization in the mother's womb. However, Mosaic Down syndrome is a rare cause.

What are the symptoms of Down syndrome?

The severity of symptoms in children with Down syndrome varies, which affects both physical and behavioral development. Some children with Down syndrome are healthy, while others have serious health issues such as congenital heart disease or hypothyroidism. Children with Down syndrome have unique, identity-defining facial and body structures, as follows:

• Small head, face, and ears, flat nose bridge, and flat back of the skull
• Has slanted upward-pointing eyes, thick head eyebrows, and may have white spots on the iris.
• Open mouth at rest, large protruding tongue, slow, slurred speech.
• Short neck, short arms, short legs, short feet, and shorter-than-average height
• Chunky with a soft trunk, not very muscular, and low muscle tone
• The gap between the nipples is narrower than in a typical child.
• Short fingers with the pinky pointing inward towards the thumb.
• Broad hands with single transverse palmar crease.
• Intelligence ranges from mild to moderate.
• Has a cheerful personality, always in a good mood, and easily smiles and laughs.

How is Down syndrome screening before birth?

Screening expectant mothers for Down syndrome and other genetic abnormalities is of great importance for both high-risk and low-risk pregnancies. The screening can be done in the first trimester, during the first three months of pregnancy, or between 12 and 16 weeks of pregnancy. There are several methods for screening for Down syndrome depending on the mother's gestational age. The following are effective screening methods for Down syndrome:

• Non-invasive prenatal testing, or NIPT, is a screening test for chromosomal abnormalities in the fetus of the mother's womb aged 12-16 weeks, using a blood sample of a mother containing genetic material from the baby's placenta (cell-free DNA). The NIPT is a screening test for chromosomal abnormalities in the fetus of the mother's womb aged 12–16 weeks using a blood sample of a mother containing genetic material from the baby's placenta (cell-free DNA). The NIPT test is a reliable pregnancy test that can detect trisomy abnormalities on chromosomes 21, 18, and 13 with an accuracy of up to 99%. The NIPT test is considered safe for the fetus, can provide results in as little as 2 weeks, and can also determine the gender of the baby in the mother’s womb as well.
• Ultrasound is used to detect abnormalities in the structure of the organs of a fetus aged 12-16 weeks. Ultrasound is used to determine the thickness of the water that collects around the baby's nuchal translucency (NT) and the nasal bone. The test is considered safe, produces results quickly, and has an accuracy of up to 80%. In addition to the ultrasound examination, the obstetrician may order additional blood work to look for biochemicals or markers in the blood to help with diagnosis accuracy.
• Amniocentesis is the analysis of the baby's chromosomes from amniotic fluid while the mother is 16-20 weeks pregnant or in the second trimester of pregnancy. This occurs when the amount of genetic material in the amniotic fluid is high. The test is used to confirm chromosome abnormalities when screening results or ultrasound results are abnormal.

How is Down syndrome diagnosed after birth?

The specialist doctor will make an initial diagnosis of Down syndrome in newborn babies based on physical features such as skull structure, facial features, or muscle tone. To confirm the diagnostic test results, a karyotype test will be performed on a blood sample of the baby to analyze chromosomes, count the number, and examine the shape and alignment of all 46 chromosomes. If there is an extra pair of chromosome 21, the baby will be diagnosed with Down syndrome.

How is Down syndrome treated?

Currently, Down syndrome is an incurable condition. Bringing a child in for a Down syndrome diagnosis soon after birth and receiving systemic treatment as soon as Down syndrome is confirmed will help children develop the skills they need in everyday life and adapt to living in a society with others. The treatment of a child with Down syndrome focuses on stimulating both physical and mental development in all aspects in order to help children reach their full potential. Down syndrome treatments are as follows:

• Physical and occupational therapy to improve muscle movement development.
• Speech therapy, speaking practice, and communication development for children based on their age.
• Participating in the special education program at school in order to practice self-help and interact with others in society.
• Receiving treatment for associated health issues or other concomitant diseases such as congenital heart disease or hypothyroidism.
• Wearing eyeglasses to correct vision problems or hearing aids for those with hearing problems.

What is the complication of Down syndrome?

• Congenital heart disease, which may require surgical treatment in some patients.
• Hypothyroidism causes weight gain, sluggishness, and drowsiness.
• Gastrointestinal disorders such as constipation or gastroesophageal reflux disease
• Eye diseases or vision impairments such as short-sightedness, far-sightedness, strabismus, conjunctivitis, and eye infection.
• Hearing impairments, such as ear infections and middle ear inflammation with pus in the ear or auditory neuropathy (NA).
• Higher risk of leukemia than normal children.
• Autism is associated with difficulties in communication, social development, and repetitive behavior.
• High risk of Alzheimer's disease.

What is the prevention of Down syndrome?

Preventing high-risk and low-risk babies with Down syndrome in both young and aging mothers is as simple as getting a pre-marital checkup or enrolling in a prenatal care program with a specialist obstetrician-gynecologist to screen for Down syndrome from the mother's blood (NIPT test) and having an appropriate treatment plan in place if the fetus is diagnosed with Down syndrome.

Down syndrome, Early screening can Help in planning the Baby’s future

Presently, advanced medical technology in screening aids in a high-precision diagnosis of Down syndrome, enabling parents to know abnormalities in advance before giving birth and helping them to plan treatment with a team of medical specialists appropriately. The doctor will provide integrative treatment, both physical and mental, as well as treatment for cognitive impairment and other necessary daily skills, to encourage children to develop in all areas suitable for their age.
 
When receiving consistent care from a team of specialist doctors and parents, including guardians at home and teachers at school, many children with Down syndrome can attend classes with normal children. With love and understanding, consistent attention, and encouragement, children with Down syndrome can live their everyday lives in society happily.