A newborn presents with hypotonia, single palmar crease, and flat nasal bridge. These clinical features are most commonly associated with which chromosomal abnormality?

1. A

   Trisomy 18

2. B

   Trisomy 21

3. C

   Trisomy 15

4. D

   Trisomy 13

Appeared in: NORCET 10 Mains

Explanation

Listen in Hindi

• The constellation of hypotonia (low muscle tone), a single transverse palmar crease, and a flat nasal bridge are hallmark clinical features of Trisomy 21 (Down syndrome).
• Trisomy 21 is the most common nonlethal trisomy, and these characteristic physical signs allow for a strong presumptive diagnosis in the neonatal period, which is then confirmed by karyotyping.
• Other associated features include up-slanting palpebral fissures, epicanthal folds, and a protruding tongue.

Why Other Options Were Wrong

• Option A: Trisomy 18, or Edwards Syndrome, presents with a different set of features.
• Option C: Full Trisomy 15 is extremely rare in live births and is typically associated with first-trimester miscarriages. It does not have a well-defined syndrome of features like Trisomy 21, 18, or 13.
• Option D: Trisomy 13, or Patau Syndrome, is characterized by severe midline defects.

Related Visual

• Visual 1: Image - A photograph of a newborn with Down syndrome, highlighting the flat nasal bridge and up-slanting palpebral fissures.
• Visual 2: Image - A close-up photograph of a hand showing a single transverse palmar crease (Simian crease).
• Visual 3: Diagram - A karyotype illustrating the three copies of chromosome 21, characteristic of Trisomy 21.

Clinical Relevance

• Nursing practice connection: Use the key finding related to Clinical manifestations of common autosomal trisomies in newborns to guide bedside assessment, documentation, and the next nursing action.
• Early recognition of the signs of Down syndrome is a critical nursing skill. It allows for prompt initiation of genetic testing for confirmation and enables the healthcare team to begin screening for common associated health problems, such as congenital heart defects (present in ~50% of cases), gastrointestinal atresia, and hypothyroidism.
• Nurses play a key role in providing emotional support and accurate information to the family, connecting them with support groups and resources like the National Down Syndrome Society.
• What if? - If the newborn presented with clenched fists and rocker-bottom feet instead of a single palmar crease, the most likely diagnosis would shift from Trisomy 21 to Trisomy 18 (Edwards Syndrome), which carries a much graver prognosis.

How to Approach the Question

• First, identify the key clinical findings presented in the question stem: hypotonia, single palmar crease, and flat nasal bridge.
• Recognize that this question is asking you to identify a genetic syndrome based on a classic cluster of physical signs.
• Systematically recall the hallmark features of the common autosomal trisomies provided in the options.
• Compare the signs in the question to the known characteristics of Trisomy 21 (Down syndrome), Trisomy 18 (Edwards syndrome), and Trisomy 13 (Patau syndrome).
• Note that the described features perfectly match the classic presentation of Trisomy 21.
• Eliminate the other options because their characteristic features (e.g., clenched hands in Trisomy 18, midline defects in Trisomy 13) are absent.

Concept Tested & Keywords

• Concept Tested: Clinical manifestations of common autosomal trisomies in newborns.
• Stem keywords: newborn, hypotonia, single palmar crease, flat nasal bridge
• Lead-in keywords: most commonly associated with
• Clinical cues: The combination of three specific physical findings (hypotonia, single palmar crease, flat nasal bridge) points to a classic triad for a specific genetic syndrome.

Question ID

QP3-Crawwj7r5Xue8XHOFh

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