Question 1: Which of the following conditions is characterized by webbing of the neck, short stature, increased carrying angle, low posterior hairline, primary amenorrhea, and short fourth metacarpal?
- A. Klinefelter syndrome
- B. Turner syndrome (Correct Answer)
- C. Cri-du-chat syndrome
- D. Noonan syndrome
- E. Down syndrome
Explanation: ***Turner syndrome***
- Characterized by **webbing of the neck**, **short stature**, and **primary amenorrhea**, which are classic features of Turner syndrome [1][2].
- The presence of a **short fourth metacarpal** is also a specific skeletal manifestation associated with this condition.
- **Short stature** in Turner syndrome is specifically explained by haploinsufficiency of the SHOX gene [1].
*Noonan syndrome*
- Presents with features like **short stature** and **cardiac anomalies**, but lacks the specific manifestations of neck webbing and primary amenorrhea.
- Typically associated with facial dysmorphisms, such as **widely spaced eyes** and a **distinctive appearance** which are not mentioned here.
*Klinefelter syndrome*
- Characterized by **47,XXY** karyotype leading to **gynecomastia** and **testicular atrophy**, rather than symptoms like webbed neck or short stature.
- Men with this syndrome usually display **delayed or incomplete puberty**, not primary amenorrhea.
*Cri-du-chat syndrome*
- Primarily associated with a **distinctive high-pitched cry** and developmental delays, rather than physical traits like webbed neck or short fourth metacarpal.
- Symptoms are more related to **chromosomal deletion** and do not include amenorrhea or features typical of Turner syndrome.
**References:**
[1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 175-177.
[2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 173-174.