There are different variables in our nature as a species that can differentiate us from others as individuals to a lesser or greater extent. For humans, one of the most contrasting conditions is trisomy 21, popularly known as Down’s Syndrome, owning its name to Dr. John Langdon Down, the first to clearly describe and delimit the condition. In 1959 Jérôme Lejeune identified it as a condition of genetic etiology (origin).
This syndrome is one of the most common congenital conditions in the world. Still, even today, there is little information and understanding on the part of the population about what Down syndrome is and how to take them into account appropriately. In the following FastlyHealarticle, we will explain all the information about Down Syndrome: causes, types, and characteristics.
Table of Contents
What is Down syndrome?
When we are gestated by the union of the sperm and the ovum, the genetic information of the parents – contained in 23 groups called ‘chromosomes’ – is united or combined in the new being. If all goes well, this information will be reproduced in each of its cells through a cell duplication process called mitosis, each of these cells harboring a total of 46 chromosomes in its nucleus.
Down syndrome, scientifically called trisomy 21, is a congenital condition that arises because there are three chromosomes of the pair of chromosomes No. 21 of the cell nucleus in the cells of the being that acquired the syndrome. This tiny but crucial alteration generates this condition that, beyond the distinguished appearance and behavior of people with this syndrome, generates some significant differences at the organic level in contrast to a person without this genetic alteration.
Being a congenital condition, it is impossible to modify. Therefore, the syndrome remains for life, but paying the required attention from the beginning and from diagnosis to development will favor the individual’s health, education, and more accessible adaptation to the syndrome.
Down syndrome: causes
Beyond the chromosomal origin of the condition, no specific causes are known for the appearance of said genetic alteration and the consequent syndrome. However, if a close relationship is found between the mother’s age and the incidence of Down syndrome:
- The incidence of the condition when mothers are less than 25 years old is 1 case in 1000 or even less.
- After reaching 35 years of age, the mother, the incidence increases to 1 in 400.
- At 45, it grows exponentially at 1 case every 30 births. This incidence is indifferent to social stratum, ethnicity, or geographical location.
It has been found that within the ovary, the best-developed eggs are selected during each ovulation of the woman during her productive life, expelling the best first and leaving the less strong for later. This cellular development of the gamete (reproductive cell) could then be a variable in the appearance of this and other congenital syndromes and mutations since a defective egg would have a greater probability of a deficient organization of the genetic information that it will transmit.
Types of Down syndrome
This condition is without gray or intermediate: the person either has it or does not. What do exist are individual differences in its manifestation, which depend both on said hereditary genetic factor and intrauterine development and, very important, care and adequate treatment once born. The sign that always occurs in Down syndrome is a cognitive delay, which in some subjects may be mild and in others moderate or severe. Based on this and the other signs present, distinctions are made in their care and treatment, more not taxonomies or classifications.
There are only three types of Down Syndrome according to their appearance. They are as follows:
- Trisomy 21 / Nondisjunction: the appearance of trisomy occurs before or during conception in the reproductive cells of one of the parents.
- Translocation: in this case, the third chromosome 21 continues to exist, but it locks together with another pair of chromosomes that is not 21. It represents 3% of the cases of Down syndrome.
- Mosaicism: represents only 1% of cases characterized by failure in the disjunction of chromosome 21 after conception. This causes not all the cells formed to present the condition, but the syndrome does not stop occurring.
It has been found that Down syndrome due to mosaicism tends to present less pronounced symptoms. However, as we reiterate, it is a typology of the appearance of the condition, but there is no classification of people with Down Syndrome.
Down syndrome: characteristics
Both family members and professionals defend that this syndrome should not be considered a disease but a condition because although they have limitations or weaknesses in their development and organic and cognitive structuring, a Down syndrome well cared for since childhood and in an appropriate environment can live with total health, tranquility, and physical and social well-being. Thus, the attributes and limitations that distinguish them can be simply signs or characteristics, not symptoms.
Those particular features of Down syndrome are:
- Short stature (but not dwarfism)
- Hypotonia or poor muscle development
- This hypotonia also influences the tongue and its ability to control it, for which it must be strengthened and trained from a young age.
- Congenital heart disease is a pathology in the formation of the heart that can be very dangerous if it is not well monitored.
- Flatter head in front and behind, and sometimes smaller
- Smaller ears and narrower ear canal
- Shorter and wider neck
- Shorter limbs and smaller, more comprehensive hands
- Eyes tilted upward and with a more rounded inner edge.
- High rates of infertility more elevated in men than in women
- Poor development of synaptic connections (between neurons) produces the expected cognitive delay in Down syndrome, which, depending on the case, ranges from mild to moderate.
This article is merely informative. At FastlyHeal .com, we do not have the power to prescribe medical treatments or make any diagnosis. We invite you to see a doctor if you present any condition or discomfort.
If you want to read more articles similar to Down Syndrome: causes, types, and characteristics, we recommend that you enter our Genetic Disorders category.
I am a Surgeon with a diploma in comprehensive ultrasound and surgical care residency, an area I am specializing in. During the exercise of my profession, I have realized the need for patients to know the diseases they suffer, and I can tell you that a large part of their complications is due to a lack of information. Being a health web writer allows me to transmit my experience, without borders, to all those readers eager for knowledge, educate them in the prevention of diseases and promote a healthy lifestyle.