A single deep crease across the center of the palm is typically seen in?

NHM UP Staff Nurse - 2019

Pathology & Genetics

Easy

Appeared in: NHM UP Staff Nurse - 2019

Explanation

A single deep crease across the palm, known as a single transverse palmar crease (or simian crease), is a classic physical sign.
This crease results from the fusion of the two normal palmar creases (proximal and distal) into a single one.
It is present in approximately 50% of individuals with Down Syndrome (Trisomy 21), making it a strong diagnostic clue.
While it can occur in the general population (1-5%), its presence often prompts a search for other features of Down Syndrome.

Option A: Mental retardation (intellectual disability) is a functional impairment, not a physical sign. While it is a common feature of Down Syndrome, it does not describe the physical crease on the palm.
Option C: Syndactyly is the webbing or fusion of fingers or toes. It is a different type of congenital limb anomaly and is not related to the creases on the palm.
Option D: Potter's Syndrome is characterized by features resulting from renal agenesis and lack of amniotic fluid, such as a flattened face (Potter facies) and limb contractures. A single palmar crease is not a typical feature of this syndrome.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain The question tests the knowledge of characteristic physical findings associated with common genetic disorders, specifically the single transverse palmar crease in Down Syndrome as background academic context rather than a clinical decision trigger.
During a newborn assessment, a nurse's identification of a single palmar crease is a crucial finding that must be documented and reported.
This finding should prompt the nurse to perform a more detailed physical examination, specifically looking for other soft markers of Down Syndrome like a flat facial profile, upward-slanting eyes, low-set ears, and hypotonia.
What if? A single palmar crease is found in an otherwise healthy-appearing newborn with no other dysmorphic features. In this case, it is likely a normal, isolated variant. However, the healthcare team should still be informed for thorough evaluation and potential parental counseling, as it can sometimes be associated with other, less obvious conditions.

How to Approach the Question

First, identify the key clinical sign described in the question: 'a single deep crease across the center of the palm'.
Recognize this as the single transverse palmar crease, also known as the simian crease.
Recall or deduce the genetic conditions listed in the options.
Associate the single transverse palmar crease with its most common syndromic cause.
Evaluate each option: Down Syndrome is strongly associated with this finding. Mental retardation is a symptom, not a physical sign. Syndactyly is fused digits. Potter's Syndrome has a different set of physical features.
Select the option that represents the condition most characteristically linked to the described physical sign.

Concept Tested & Keywords

Concept Tested: The question tests the knowledge of characteristic physical findings associated with common genetic disorders, specifically the single transverse palmar crease in Down Syndrome.
Stem keywords: single deep crease, center of the palm
Lead-in keywords: typically seen in

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