Trisomy 21, also commonly called Down syndrome, is a genetic abnormality that results from a chromosomal alteration. The human karyotype consists of 23 pairs of chromosomes, totaling 46 chromosomes, but the carriers of this anomaly have an extra chromosome in their 21st pair of chromosomes, thus having 47 chromosomes in their karyotype.
Unfortunately, there is no cure for trisomy 21, there are only a few forms of therapy to alleviate the manifestations of this anomaly. Some therapies performed by patients with this syndrome are physical therapy, psychomotor stimulation, and speech therapy.
In statistical data, about 15 thousand people are carriers of this anomaly, in Portugal. One in 700 babies is born with trisomy 21, between 100 to 120 children a year, 2 a week.
The risk of being born a child with t21 increases with the mother's age. From the age of 35 onwards, the risk is higher. However, any couple can have a child with t21. Statistically speaking, at age 30, 1 in every 900 babies is born with this anomaly, while at age 40, 1 in every 100 babies is a carrier of t21.
20 years -> 1/1530
30 years -> 1/900
35 years -> 1/360
40 years -> 1/100
45 years -> 1/30
Characteristics of carriers
People with this anomaly have several characteristics that are different from what we are used to seeing.
Patients with this syndrome have numerous physical characteristics in common with each other, which we highlight:
· Small, rounded ears;
· Almond-shaped eyes;
· Wide and flat face;
· Small nose;
· Short neck;
· Excessive skin on the back of the neck;
· Short;
· Dental anomalies;
· More curved roof of the mouth;
· Large tongue;
· Spaced toes;
· Small feet;
· Small hands and wide fingers.
As for the psychological characteristics, the following stand out:
· Disturbance of intellectual development;
· Speech difficulties;
· Slow and late development;
· Limited attention span;
· Learning difficulties;
· Poor brain development (IQ between 20 and 75).
PRE CHRISTMAS DIAGNOSIS
What is it?
Prenatal diagnosis is the set of procedures aimed at early detection of fetal malformations, that is, whether an embryo or fetus is a carrier or not of a congenital anomaly, which, depending on the evolution and duration of the pregnancy, are performed different obstetric ultrasounds.
How to diagnose?
Prenatal diagnosis is usually carried out during pregnancy. Several screening tests are performed, such as:
· NIPT (non-invasive prenatal testing);
· Amniocentesis (invasive examination);
· Chorionic villi biopsy;
· Early dating ultrasound (the first ultrasound that the pregnant woman wants to perform, before 11 weeks of pregnancy, to know how old she is);
· 1st-trimester morphological ultrasound (performed between 11 and 13 weeks);
· 2nd-trimester morphological ultrasound (occurs around 21-22 weeks, when it is already possible to detect the baby's sex);
· Morphological ultrasound of the 3rd trimester (occurs at 32 weeks of pregnancy (28 and 36 weeks in some situations), where the baby's condition is assessed).
Any pregnant woman can resort to these diagnoses, however, these tests are fundamentally indicated in the following situations:
· Increased risk of the baby being a carrier of the anomaly;
· Anomalies diagnosed by ultrasound;
· Risk of malformations due to the use of medication and/or radiation;
· Serious maternal illnesses;
· Personal or family history of the genetic, metabolic, or chromosomal disease;
· Previous obstetric complications such as dead fetus or malformed fetus;
· Significant changes in fetal growth;
· Complicated twin pregnancy;
· Maternal age > 38 years;
· Depending on each situation, it may be necessary to request specific screening tests such as amniocentesis or chorionic villi biopsy, fetal magnetic resonance, fetal echocardiogram, among others.
ASSOCIATED PROBLEMS
Being a carrier of this syndrome implies a higher risk of developing the following problems:
· Intellectual development disturbance / cognitive deficit, of varying severity;
· In about half of the cases, there is structural heart disease (congenital heart disease);
· Speech problems or language disorders, difficulty chewing, breathing changes, or sleep disturbances due to macroglossia and a small oral cavity. Some dental interventions can help to expand the jaw;
· Lack of muscle strength (hypotonia) and motor problems;
· Ophthalmological problems;
· Hearing loss;
· Cardiovascular problems from birth.
T21 AND COVID-19
The analyzes and studies carried out have shown that there is a greater risk of infection in people with this anomaly, and these become part of the priority groups for vaccination against COVID-19. There is a real impact of this virus in this population, according to an article published in March 2021, by the Directorate-General of Health (DGS).
INTERNATIONAL DOWN SYNDROME DAY
The international day of Down syndrome marks the 21st of March, dates this proposal by the international association of Down syndrome (Down Syndrome International). The 21st day corresponds to the 21st pair of chromosomes, which has one more chromosome, that is, 3 chromosomes (the number corresponding to March).
This day was made official by the United Nations (UN) in 2012 and is celebrated every year in about 193 countries.
The thematic colors, blue and yellow, symbolize solidarity with patients with the syndrome.
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