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 combination of hypotonia (low muscle tone), a single transverse palmar crease (Simian crease), and a flattened nasal bridge are hallmark physical characteristics of a newborn with Trisomy 21.
• Trisomy 21, also known as Down syndrome, is the most common chromosomal disorder and the most frequent genetic cause of intellectual disability.
• These distinct features allow for a presumptive clinical diagnosis at birth, which is then confirmed by karyotype analysis.

Why Other Options Were Wrong

• Option A: Trisomy 18, or Edwards syndrome, presents with a different set of features, including severe growth restriction, clenched hands with overlapping fingers, rocker-bottom feet, and micrognathia (small jaw).
• Option C: Full Trisomy 15 is extremely rare and typically results in miscarriage during the first trimester. It is not associated with a recognized syndrome presenting with the features described.
• Option D: Trisomy 13, or Patau syndrome, is characterized by severe midline defects. Key features include holoprosencephaly (failure of the brain to divide), microphthalmia (small eyes), cleft lip and/or palate, and polydactyly (extra fingers or toes).

Related Visual

Clinical Relevance

• Nursing practice connection: Use the key finding related to Clinical manifestations of common autosomal trisomies to guide bedside assessment, documentation, and the next nursing action.
• Early identification of the features of Down syndrome is a critical nursing responsibility. It allows for prompt initiation of a full diagnostic workup, including a chromosomal analysis (karyotype).
• Nurses play a key role in screening for associated comorbidities. About 50% of infants with Down syndrome have congenital heart defects, so an echocardiogram is a standard part of the initial evaluation.
• Providing sensitive, accurate information and emotional support to the family is paramount. The nurse can connect the family with support groups and early intervention services to optimize the child's developmental outcomes.

How to Approach the Question

• First, carefully read the question and identify the key clinical findings presented in the newborn: hypotonia, single palmar crease, and flat nasal bridge.
• This is a clinical scenario question that requires you to recall the classic presentations of different genetic syndromes.
• Systematically review the options provided: Trisomy 18, 21, 15, and 13.
• Mentally associate each trisomy with its most common physical features.
• Match the triad of symptoms from the question stem to the corresponding chromosomal abnormality. The combination of hypotonia, single palmar crease, and a flat facial profile is pathognomonic for Trisomy 21.
• Eliminate the other options by confirming their features are different. Trisomy 18 involves clenched hands and rocker-bottom feet. Trisomy 13 involves severe midline defects like clefting and polydactyly.

Concept Tested & Keywords

• Concept Tested: Clinical manifestations of common autosomal trisomies.
• Stem keywords: newborn, hypotonia, single palmar crease, flat nasal bridge, chromosomal abnormality
• Lead-in keywords: most commonly associated with
• Negative lead-in flag: false

Question ID

QP3-Crawwj7r5Xue8XHOFh

Copy ID

Reference Book

E6 Obstetrics Williams p. 5-15

E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 407-409