Down syndrome

 Down Syndrome:

Down syndrome (trisomy 21) is a genetic disorder caused by the presence of all or a portion of a third chromosome 21. It is usually associated with developmental delays, mild to moderate intellectual disability, and characteristic physical features. There are three types of Down syndrome, all with the same features: Trisomy 21, the most common type ; Mosaic Down syndrome, and Translocation Down syndrome.

Objectives:

  . Describe the etiology of Down syndrome.

  .Identify atrial septal defects as the most common cardiac   abnormalities in patients with Down syndrome.

  .Summarize the use of ultrasound, amniocentesis, and   chorionic villus sampling in the prenatal diagnosis of Down   syndrome.

  .Outline the importance of collaboration and communication   among the interprofessional team to enhance the delivery of   care and improve outcomes for patients affected by Down   syndrome.

  

Signs and symptoms:

Those with Down syndrome nearly always have physical and intellectual disabilities. As adults, their mental abilities are typically similar to those of an 8- or 9-year-old. At the same time, their emotional and social awareness is very high. They can have poor immune function and generally reach developmental milestones at a later age. They have an increased risk of a number of health concerns, such as congenital heart defect, epilepsy, leukemia, and thyroid diseases.

1. Mental impairment    99%

2. Stunted growth          90%

3. Umbilical hernia         90%

4. Increased skin on back of neck  80%

5. Low muscle tone        80%

6. Narrow roof of mouth   76%

7. Flat head                       75%

8. Flexible ligaments         75%

9. Proportionally large tongue  75%

10. Abnormal outer ears           70%

11. Flattened nose                  68%

12. Separation of first and second toes   68%

13.  Abnormal teeth            60%

14. Slanted eyes                  60%

15. Shortened hands            60%

16. Short neck                     60%

17. Obstructive sleep apnea  60%

18.  Bent fifth finger tip       57%

19.  Brushfield spots in the iris   56%

20.  Single transverse palmar crease   53%

21.  Protruding tongue        47%

22.  Congenital heart disease   40%

23.  Undescended testicles       20%

Pathophysiology:

An extra copy of chromosome 21 is associated with Down syndrome, which occurs due to the failure of chromosomes 21 to separate during gametogenesis, resulting in an extra chromosome in all the body cells. Robertsonian translocation and isochromosome or ring chromosome are the other 2 possible causes of trisomy 21. Isochromosome is a condition when 2 long arms separate together instead of the long and short arms while in Robertsonian translocation. This occurs in 2% to 4% of the patients. The long arm chromosome 21 is attached to another chromosome, mostly chromosome 14. In mosaicism, there are 2 different cell lines because of the error of division after fertilization.

Treatment:

The management of patients with Down syndrome is multidisciplinary. Newborns with suspicion of Down syndrome should have a karyotyping done to confirm the diagnosis. The family needs to be referred to the clinical geneticist for the genetic testing and counseling of both parents.

Parental education is one of the foremost aspects regarding the management of Down syndrome, as parents need to be aware of the different possible conditions associated with it so that they can be diagnosed and treated appropriately. Treatment is basically symptomatic, and complete recovery is not possible.

These patients should have their hearing and vision assessed, and as they are more prone to have cataracts, timely surgery is required. Thyroid function tests should be done on  a yearly basis and, if deranged, should be managed accordingly.

A balanced diet, regular exercise, and physical therapy are needed for optimum growth and weight gain, although feeding problems improve after cardiac surgery. 

Cardiac referral should arranged for all the patients regardless fo the clinical signs of congenital heart disease. If present, this should be corrected within the first 6 months of life to ensure optimum growth and development of the child.

Other specialities involved include a developmental pediatrician, pediatric pulmonologist, gastroenterologist, neurologist, neurosurgeon, orthopedic specialist, child psychiatrist, physical and occupational therapist, speech and language therapist, and audiologist.