The down's syndrome is a congenital chromosome abnormality and is also known as:

AIIMS Jodhpur SNO-2023

Pathology & Genetics

Easy

Appeared in: AIIMS Jodhpur SNO-2023

Explanation

Down's syndrome is a genetic condition resulting from an extra copy of chromosome 21.
This specific chromosomal abnormality is medically termed 'Trisomy 21', where 'tri-' refers to the presence of three chromosomes instead of the usual pair.
It is the most frequently occurring chromosomal disorder and is associated with characteristic physical features and developmental delays.
The diagnosis is confirmed by a karyotype analysis, which visually represents the chromosomes and would show the extra 21st chromosome.

Option A: Trisomy 20 is a rare chromosomal condition, typically seen in mosaic form, and is not associated with the clinical presentation of Down's syndrome.
Option B: Trisomy 18 is the genetic basis for Edwards Syndrome, a different and more severe condition than Down's syndrome.
Option C: This is a biologically impossible condition. Humans have 23 pairs of chromosomes, so a 'chromosome 31' does not exist.

Visual 1: Karyotype Diagram - A human karyotype showing three copies of chromosome 21, clearly illustrating the genetic basis of Trisomy 21.
Visual 2: Infographic - A comparative chart showing the key physical features of Down Syndrome (Trisomy 21), Edwards Syndrome (Trisomy 18), and Patau Syndrome (Trisomy 13) side-by-side.

Clinical Relevance

Nursing practice connection: Knowing Identification of the chromosomal basis for Down's syndrome 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 newborns with Down's syndrome, from providing initial education and emotional support to coordinating care with specialists.
Understanding the genetic basis allows nurses to explain prenatal screening tests (like non-invasive prenatal testing - NIPT) and diagnostic tests (like amniocentesis) to expectant parents.
What if? - If a prenatal screen comes back with a high risk for Trisomy 18 instead of Trisomy 21, the nurse's counseling would shift significantly. The focus would be on preparing the family for a much poorer prognosis and the high likelihood of infant mortality, which is characteristic of Edwards Syndrome.

How to Approach the Question

First, identify the core of the question, which is asking for the specific medical name for the chromosomal abnormality in Down's syndrome.
This is a factual recall question. Access your knowledge of common genetic disorders.
Recall that 'tri-' means three and 'somy' refers to the chromosome. 'Trisomy' means three copies of a chromosome.
Associate the most common trisomies with their numbers: Down's syndrome is Trisomy 21, Edwards syndrome is Trisomy 18, and Patau syndrome is Trisomy 13.
Evaluate the options. Eliminate impossible options like 'Trisomy 31' as humans only have 23 pairs of chromosomes.
Select the option that correctly matches Down's syndrome with its corresponding trisomy number.

Concept Tested & Keywords

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