What is Down syndrome?

NHM UP Staff Nurse-2023 Shift-2nd

Pathology & Genetics (E5)

Easy

Appeared in: NHM UP Staff Nurse-2023 Shift-2nd

Explanation

Down syndrome, also known as Trisomy 21, is a genetic condition caused by the presence of a full or partial extra copy of chromosome 21.
This extra genetic material alters the course of development and causes the characteristic physical and intellectual features associated with the syndrome.
It is the most common chromosomal disorder and a leading cause of intellectual disability, occurring in about 1 in 700 live births.

Option A: An extra copy of chromosome 19 (Trisomy 19) is a rare chromosomal abnormality that is typically not compatible with life, often resulting in early miscarriage.
Option B: An extra copy of chromosome 18 results in Edwards syndrome (Trisomy 18), a distinct and severe genetic disorder with a high mortality rate in the first year of life.
Option D: Chromosome 23 refers to the sex chromosomes (X and Y). An extra copy leads to conditions like Klinefelter syndrome (XXY) or Triple X syndrome (XXX), which affect sexual development and fertility, not Down syndrome.

Clinical Relevance

Nursing practice connection: Knowing Genetic disorders and chromosomal abnormalities helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses play a crucial role in supporting families of children with Down syndrome, from providing initial education and counseling at birth to coordinating care for associated health issues like congenital heart defects, hearing/vision problems, and developmental delays.
Early intervention programs are critical for children with Down syndrome. Nurses can educate parents on the importance of physical, occupational, and speech therapy to help children reach their full potential.
What if? If a prenatal screening test (like a nuchal translucency scan or non-invasive prenatal testing) comes back with a high risk for Down syndrome, the next step is not a diagnosis but counseling the parents about definitive diagnostic tests like amniocentesis or chorionic villus sampling (CVS), which carry a small risk of miscarriage.

How to Approach the Question

This is a factual recall question testing knowledge of common genetic disorders.
First, identify the core concept in the question stem: 'Down syndrome'.
Recall the specific chromosomal abnormality associated with this condition. The name 'Trisomy 21' is a key piece of information to remember.
Evaluate each option against this knowledge. 'Trisomy' means an extra (third) chromosome, and '21' specifies which chromosome is affected.
Eliminate options that describe other well-known trisomies (like Trisomy 18 for Edwards syndrome) or involve different chromosome types (like chromosome 23, the sex chromosomes).

Concept Tested & Keywords

Q90I8zCU7FfoK2nLC7gcNi

E6 Kaplan Sadock's Synopsis of Psychiatry-2022 (pp 1-3768 of 3768) p. 330-332

E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed p. 176-178