Down's syndrome

Trisomy 21; mongolism (obsolete).

INCIDENCE

The most common and well-known form of chromosomal abnormalities is known as Down syndrome. The total incidence ranges from one in every 660 to one in every 800 live births in the Caucasian, Japanese, and American Negro populations, respectively. These are just general estimates because the likelihood of a child being born with Down syndrome is highly influenced by the mother's age. When the mother is older than 35 years old, the risk is significantly increased. It can have an impact on both males and females.

HISTORY

Children with Down syndrome have been known about for a good number of years. Dr. Langdon Down, who worked in the early part of the 20th century, provided a detailed and accurate description of all of the symptoms that were linked with the illness.

CAUSATION

A chromosomal aberration is what leads to the development of Down syndrome, and there are two separate pathways via which the abnormality might take place. The most prevalent procedure takes place when an additional chromosome is introduced in position 21, and it is called mosaicism. That is why it is called trisomy 21. Under these conditions, the total number of chromosomes will be 47, which is an increase from the standard count of 46 chromosomes. This happens when chromosomal pairs do not successfully separate during the process of producing the egg or the sperm. This phenomenon is referred to as "non-dysjunction." The older a mother is, the higher her risk of having a child with this condition is. This effect is responsible for the majority of cases of Down syndrome in newborns. However, in approximately 5% of cases, an additional chromosome is attached to one of the existing chromosomes. This process is referred to as "translocation." In light of these facts, the impacted infant will have the standard number of 46 chromosomes across their entire genome. However, there will be one chromosome that is a "compound" in this number. A 'balanced translocation' can have either parent as the carrier of the mutation. There is no correlation between the mother's age and an increased risk of having a kid with this particular form of Down syndrome. (The circumstance is referred to as a balanced translocation when the individual, in this case the mother, involved is clinically normal.) However, the clinical effects that this compound chromosome will have are still going to be the same as they were in the newborn who had 47 chromosomes.
The likelihood of a woman giving birth to a child with Down syndrome as a result of nondysjunction increases as she gets older. When a person is 30 years old, the risk is believed to be one in 800, but when a person is 44 years old, the risk might reach as high as one in 50. There is no correlation between an older mother's age and an increased risk of the syndrome in cases where the illness is caused by translocation. If the translocation is carried by the mother, there is a 10% chance of having further infants with Down syndrome. If the translocation is carried by the father, there is a 2.5% chance.
There are additional, extremely uncommon types of chromosomal abnormalities that can result in the development of a newborn with Down syndrome. When providing genetic counseling to expecting parents who already have a child with Down syndrome, it is imperative that these factors be taken into consideration.
Amniocentesis, which is used for prenatal diagnosis, can be performed sometime around the 16th week of a pregnancy. Chorionic villus sampling is another method of prenatal diagnostics that can be performed between the tenth and twelfth week of pregnancy. In cases when there is a history of Down syndrome in the mother's family or when the mother is getting close to the end of her reproductive years, a blood test may be performed. In specialist centers, tests are currently being conducted to refine an ultra-sound technology that can detect particular anomalies in the early stages of pregnancy.

CHARACTERISTICS

Characteristics of the face include an epicanthal fold that is prominent and eyes that are set at an angle. A short neck in conjunction with a relatively tiny head that is clearly more convex at the rear is a characteristic trait. The ears are not very huge, but the tongue is quite large and has a characteristic pattern of deep furrows across its surface.
Cataracts, squints, and nystagmus are all examples of eye abnormalities that may be present in a child with Down syndrome; however, it is important to note that not all of these abnormalities are always present. The majority of children with Down syndrome have what are called Brushfield's spots, which appear as little white flecks on the iris. These spots do not interfere with a person's vision in any way, but they are a useful diagnostic trait.
The limbs are not very long, which results in a final height that is on the shorter side of the average. The proportions of the body are appropriate (cf achondroplasia).
In many babies, the fingers are small and stubby, and the little finger has the distinctive intumescence of a baby finger. In most cases, there is only one crease in the palmar region. Although this is a characteristic that is frequently seen in children who have a learning problem of some kind, single palmar wrinkles on the hands are also common in many persons who have intellectual abilities that are considered to be normal.
One distinguishing quality of feet is that the great toe is set at a considerable distance from the other toes of the foot. When one examines the bottoms of the feet, this becomes immediately apparent.
As a result of their always low muscle tone, kids born with Down syndrome are typically described as being "floppy." The subsequent delayed physical development continues, and walking does not begin until a later stage than is typical.
A newborn born with Down syndrome can be identified right away based on these distinct symptoms that appear shortly after birth. Chromosome analysis are going to be required in order to provide verification.
It is becoming increasingly apparent that there is a delay in development as construction continues. Intellectual development in a person's first few months or years of life is frequently delayed, although it can still fall within the realm of what is considered normal. As the child with Down syndrome grows older, it is observed that he or she is falling further and further behind the child's peers. Initially, the kid may attend regular schools for his or her education; but, by the time the child is old enough to attend secondary school, it is almost always determined that the child need special accommodations in order to attain his or her full potential.
Personality: The majority of youngsters diagnosed with Down syndrome grow up to be affectionate, joyful young adults who are a joy to be around. They have a natural sense of humor, which can contribute significantly to the quality of life within the family.
Other characteristics often associated with Down syndrome include the following:
About forty percent of babies born with Down syndrome have a cardiac defect that was present at birth. The most prevalent anomalies are atrial septal defects, ventricular septal defects and/or patent ductus arteriosus.
Infections of the upper respiratory tract are quite prevalent in infants and children of all ages. This is attributable in part to the narrowness of the air channels, as well as a compromised immune system; nevertheless, this is also the case due to the fact that the air passageways are small. Ear infections are also very prevalent and can cause conductive deafness if not treated properly.
About twenty percent of children who have Down syndrome also suffer from thyroid illness, which can take the form of either hypo- or hyperthyroidism. The first scenario is the most typical.
Children with Down syndrome have an increased risk of developing acute lymphocytic leukemia, which accounts for about five percent of all fatalities that occur in young children.

MANAGEMENT IMPLICATIONS

Learning difficulty is a characteristic that is present in all children with Down syndrome. This issue requires careful evaluation and management. The newborn and the young kid will develop in a manner that is consistent with that of his or her contemporaries, albeit at an ever slower rate. Therefore, it is essential that playthings be offered that are appropriate for the developmental stage that has been reached rather than the chronological age of the child.

Help from a physiotherapist should be sought out as soon as possible for a child diagnosed with Down syndrome. Help can be offered to encourage movement, and parents can also be advised on how to manage their hypotonic baby with the help of this help. The proposed exercises will also help in the control of the recurrent respiratory tract infections to which Down's newborns are particularly susceptible. These infections can be very harmful.

The typical routine for attendance at playgroup and nursery schools can be followed, and many children with Down syndrome do quite well in the lower levels of the mainstream infant school. However, by the time the youngster is seven or eight years old, it is clear that the work is becoming increasingly challenging for the child. Because of his/her short stature, poor coordination, and relatively weak muscles, he/she has difficulty keeping up with and participating in activities with his/her peers. At this point in time, doing a thorough assessment is of the utmost importance in order to establish the next steps to take. In most cases, it will be determined that the individual need some form of specialized instruction or additional resources. The kind of education that can be obtained will largely be determined by the resources that are readily available in the area.

Children who have Down syndrome should, if at all feasible, be integrated into a typical family setting. Their warm and joyful personality blossoms within the confines of the love and safety provided by the unit of the family.
Eye abnormalities: Squints need to be evaluated and corrected, either using orthoptic or surgical procedures, in order to prevent amblyopia. This is significant because children with Down syndrome require as much sensory stimulation as is humanly possible in order to develop to their full potential.
Infections of the respiratory tract, which are usually connected with infections of the middle ear, will require therapy that is adequate and sustained. Children with Down syndrome frequently suffer from bronchitis, which typically develops after an infection of the upper respiratory tract and requires appropriate treatment.
Evaluation and therapy are required for deafness that is brought on by recurrent infections in the middle ear. Hearing may often be accurately evaluated through the use of distraction tests.
Myringotomy, which involves removing sticky secretions from the middle ear, might be all that is required in the early stages of the condition. However, many children with Down syndrome will eventually require the use of hearing aids.
When caring for a child with Down syndrome, thyroid dysfunction is an issue that must always be kept in mind. Caregivers should be on the lookout for any abnormal slowing of activity that is accompanied by specific hair loss as well as a hoarsening of the voice in order to rule out the potential of hypothyroidism. This condition can be remedied with thyroxine treatment. The condition of one's thyroid must be monitored on a regular basis throughout one's entire life in order to ensure that the appropriate amount of this hormone is being administered.
It is likely that congenital cardiac disease was discovered during the course of normal medical tests. If a flaw was discovered, subsequent checks at regular intervals and the application of the appropriate treatment, if required, should be carried out.
Maintaining a healthy weight is also very important for a child who has Down syndrome. These children tend to be somewhat inactive, which contributes to their tendency to accumulate excess weight. Counsel on diet and nutrition is beneficial.