A short webbed neck is a characteristic physical feature commonly associated with which human chromosomal disorder or syndrome?

Introduction / Context:
Chromosomal disorders in humans often have characteristic physical features that help doctors recognise them clinically. One such feature is a short neck with skin folds that make the neck appear webbed. Identifying which syndrome commonly shows this sign is a common question in basic genetics and human health topics. This question focuses on matching the webbed neck feature to the correct chromosomal disorder.

Given Data / Assumptions:

• The options include Down syndrome, Turner syndrome, Klinefelter syndrome, Cri du chat syndrome, and Edward syndrome.
• Short webbed neck is the main feature mentioned in the stem.
• We assume classical textbook descriptions of these syndromes.
• Other associated features like sex chromosome pattern and stature are not given but may guide reasoning.

Concept / Approach:
Turner syndrome occurs in females who have a complete or partial loss of one X chromosome, giving a karyotype of 45,X or variants. Typical features include short stature, webbed neck, broad chest with widely spaced nipples, and underdeveloped ovaries leading to infertility. Down syndrome is associated with trisomy 21 and has facial features such as flat facial profile and epicanthic folds. Klinefelter syndrome occurs in males with an extra X chromosome 47,XXY and shows tall stature and small testes. Cri du chat syndrome and Edward syndrome have other distinctive features. Short webbed neck is classically associated with Turner syndrome.

Step-by-Step Solution:
Step 1: Recall the hallmark phenotype of Turner syndrome in girls, including short height and webbed neck. Step 2: Recognise that the neck in Turner syndrome often shows skin folds running from the mastoid region to the shoulders, giving a webbed appearance. Step 3: Note that Down syndrome, due to trisomy 21, has characteristic facial features but not a classic webbed neck. Step 4: Klinefelter syndrome affects males and is associated with tall stature, gynaecomastia, and infertility, without webbed neck as a typical sign. Step 5: Cri du chat syndrome is named for a cat like cry in infants and involves a deletion on chromosome 5, with different facial features. Step 6: Edward syndrome trisomy 18 has clenched fists and other malformations, but webbed neck is not the key distinguishing feature. Step 7: Therefore, the syndrome most strongly linked with webbed neck is Turner syndrome.

Verification / Alternative check:
Clinical genetics references and paediatrics textbooks list webbed neck as a classic physical feature of Turner syndrome. Photographs and case descriptions repeatedly highlight this along with short stature. In contrast, the main remembered features for Down syndrome centre on mental retardation, facial appearance, and single palmar crease, while Klinefelter syndrome is identified by tall slender males with hypogonadism. Quick revision tables for chromosomal disorders also match webbed neck specifically with Turner syndrome.

Why Other Options Are Wrong:
Down syndrome does not usually include a webbed neck as a defining sign. Klinefelter syndrome has a different set of characteristics in males and is not known for a webbed neck. Cri du chat syndrome is associated with microcephaly and cat like cry rather than neck webbing. Edward syndrome has severe congenital anomalies but does not typically list webbed neck as a classical feature. Thus none of the other options match the description as precisely as Turner syndrome.

Common Pitfalls:
A common error is to guess Down syndrome because it is the most familiar chromosomal disorder, but this question targets a specific physical sign not typical of Down syndrome. Another pitfall is mixing up Turner and Klinefelter syndromes because both involve sex chromosomes. Remember that Turner syndrome affects females with one X chromosome and includes webbed neck, whereas Klinefelter syndrome affects males with an extra X chromosome without this neck feature.

Final Answer:
A short webbed neck is characteristic of Turner syndrome.