Trisomy 21
Trisomy 21, which is also known as Down Syndrome, is a
genetic mutation where there is an extra chromosome
21 (Akhtar & Bokhari, 2023). Humans typically have a pair of
chromosome 21 whereas a person with Down Syndrome has
three total copies of chromosome 21. Instead of there being
46 chromosomes, there are 47 (Akhtar & Bokhari, 2023).
Trisomy 21 causes physical and intellectual disabilities and
has characteristic features. These characteristic features
include facial features such as low nasal bridge, low-set ears,
and protruding tongue (Story, 2024).
How Trisomy 21 Occurs
Trisomy 21 occurs when chromosome 21 is unable to separate
during gametogenesis, causing an extra chromosome (Akhtar
& Bokhari, 2023). This extra chromosome is translocated
elsewhere, typically to chromosome 14. There is a greater
chance of Trisomy 21 when the parental age is greater or
when there is exposure to teratogens (Story, 2024).
Risks and Concerns of Trisomy 21
From the moment of birth, babies born with Trisomy 21 have
the chance of facing immediate health issues. These health
concerns include congenital heart defects such as
atrioventricular septal defect (AVSD) or ventricular septal
defect (VSD). Roughly half of babies born with Trisomy 21 are
born with a congenital heart defect. AVSD accounts for 40% of
those heart defects and VSD accounts for 32% (Akhtar &
Bokhari, 2023). About 30% of babies with Trisomy 21 are born
with multiple heart defects. Trisomy 21 is also known to cause
structural disorders of the GI tract such as duodenal atresia
and Hirschsprung's Disease (Akhtar & Bokhari, 2023). Trisomy
21 can also cause disorders of the blood including
hematological abnormalities in a newborn with Down
Syndrome (HANDS) and leukemia. Those with Trisomy 21 are
ten times more likely to develop leukemia (Akhtar & Bokhari,
2023). They are also more prone to have vision issues
strabismus and cataracts (Story, 2024). Trisomy 21 is also
associated with learning and developmental disabilities. Adults
with trisomy 21 are at a higher risk of other health conditions
such as early onset Alzheimer's at the age of 50, which occurs
in 50% (Story, 2024).
Preparing for the Future with Trisomy 21
It's important to establish a care team to include a
pediatrician, cardiologist, and specialists that aid in cognitive
and developmental development (Akhtar & Bokhari, 2023).
Establishing care with specialists can help with early
interventions for physical and speech therapy. Understanding
the possibility of conditions associated with trisomy 21 is
important so that they can be treated and diagnosed
effectively. It’s important to be prepared for routine
screenings for hearing and vision. Exercise, physical therapy,
and a proper diet are considered a necessity to ensure proper
growth and weight gain (Akhtar & Bokhari, 2023). Even though
the life expectancy has increased for those with trisomy 21,
they have a shorter life expectancy than those without it.
References
Akhtar, F. & Bokhari, S (2023). Down
Syndrome. StatPearls. National Library of
Medicine. https://www.ncbi.nlm.nih.gov/books/NBK526016/
Story, L. (2024). Pathophysiology: A practical approach (5th
ed.). Jones & Bartlett.
