Growth and Development Practice Questions

Q: An infant presents with features of premature ageing, growth failure, and early-onset atherosclerosis. The child has a characteristic progeroid appearance. Which of the following genes is most commonly associated with this condition? Options:

LMNA gene. ***LMNA gene*** - Mutations in the **LMNA gene** lead to the production of **progerin**, a defective form of **lamin A** protein, which causes **Hutchinson-Gilford progeria syndrome**. - This condition is characterized clinically by **failure to thrive**, **alopecia**, **sclerodermatous skin**, and early-onset **atherosclerosis** often leading to myocardial infarction or stroke. *WRN gene* - Mutations in the **WRN gene** (encoding a **DNA helicase**) cause **Werner syndrome**, which presents as **adult-onset** progeria rather than infantile. - Werner syndrome patients typically present in late adolescence or early adulthood with short stature, **cataracts**, and premature graying, lacking the early infantile onset of Hutchinson-Gilford. *C-KIT gene* - Mutations in the **C-KIT gene** (encoding a **tyrosine kinase receptor**) are primarily associated with **gastrointestinal stromal tumors (GIST)** and **piebaldism**. - They are not associated with progeroid syndromes or premature aging, but rather with defects in hematopoiesis and melanogenesis. *TP53 gene* - Mutations in the **TP53 gene** are strongly associated with **Li-Fraumeni syndrome**, which predisposes patients to a wide spectrum of childhood and adult-onset **cancers**. - While p53 has roles in **cellular senescence**, it is not the primary causative gene for classic progeroid syndromes like Hutchinson-Gilford.

Q: A 19-year-old boy presents with long limbs and hypermobility of joints. Genetic analysis shows a mutation in the FBN1 gene. What is the most likely diagnosis?

Marfan syndrome. ***Marfan syndrome*** - This condition is caused by a mutation in the **FBN1 gene** on chromosome 15, which codes for **fibrillin-1**, a key component of connective tissue microfibrils. - Clinical features classically include **dolichostenomelia** (long limbs), **arachnodactyly** (long, thin fingers), **joint hypermobility**, and a high risk of **aortic root dilation** or dissection. *Ehlers–Danlos syndrome* - Primarily characterized by **skin hyperextensibility** and excessive tissue fragility, rather than the skeletal overgrowth seen in Marfan syndrome. - Mutations typically involve genes encoding **collagen** or enzymes involved in collagen processing (e.g., **ADAMTS2** or **PLOD1**), not the *FBN1* gene. *Homocystinuria* - Presents with a Marfanoid habitus but is distinct due to the presence of **intellectual disability** and **thrombotic events** (due to hypercoagulability). - It is an **autosomal recessive** metabolic disorder caused by **cystathionine beta-synthase deficiency**, not a fibrillin defect. *Loeys–Dietz syndrome* - While it shares features like aortic aneurysm and skeletal findings, it is often distinguished by **hypertelorism**, **bifid uvula**, and **cleft palate**. - It is caused by mutations in **TGFBR1** or **TGFBR2** genes, which regulate the TGF-beta signaling pathway, distinct from the *FBN1* pathology of Marfan syndrome.

Q: A 12-year-old girl is being evaluated for pubertal development. On examination, she has early breast development and sparse, thin pubic hair. Based on the Tanner staging diagram provided, what stage does she correspond to?

Stage II. ***Stage II*** - Stage II breast development (thelarche) is characterized by **breast bud development**, which appears as a small mound of breast tissue and enlargement of the **areola**. - Pubic hair in Stage II typically consists of sparse, long, pigmented, straight, or slightly curly hair, mainly along the **labia majora**. *Stage I* - This represents the **prepubertal** state, where there is **no palpable breast tissue** and the nipples lie flat against the chest wall. - There is **no sexual hair** (vellus hair only) present in the pubic region during this stage. *Stage III* - In this stage, the breast and areola are further enlarged, though they continue to have a single contour without separation of the areola from the breast mound. - Pubic hair becomes darker, coarser, curlier, and spreads over the **mons pubis**, exhibiting a more typical adult-like texture but in a smaller area. *Stage IV* - This stage features the **areola and papilla (nipple)** forming a secondary mound projecting above the contour of the rest of the breast. - Pubic hair resembles adult type but covers a smaller area than in a mature adult, with **no spread to the medial surfaces of the thighs**.

Q: Due to persistence of the Moro reflex, a child will have difficulty achieving which of the following developmental milestones?

Rolling over. ***Rolling over*** - The persistent **Moro reflex** causes involuntary abduction and extension of the arms, which interferes with the integration of motor patterns required for independent **rolling over**. - Typically, the Moro reflex integrates (disappears) by **3 to 4 months** of age, which coincides closely with the timing of when an infant should be mastering the skill of rolling. *Neck holding* - **Neck holding** (or head control) is typically achieved by **2 to 3 months** of age, which overlaps with the later stages of the Moro reflex persistence. - Because the Moro reflex is triggered by a sudden change in head position or support, it primarily affects limb movement rather than the primary strengthening of the neck muscles required for head control. *Sitting with support* - **Sitting with support** is generally achieved around **5 to 6 months** of age, well after the Moro reflex should have integrated. - Persistence of the reflex at this age would indicate a severe **neurological disorder** rather than just a simple delay in motor development. *Sitting without support* - **Sitting without support** is a later developmental milestone, typically reached by **7 to 8 months** of age. - By this stage, the Moro reflex should have long since disappeared; if present, it is pathognomonic for **cerebral palsy** or other significant brain injury, not merely a hurdle for this specific milestone.

Q: At what age can a child typically laugh aloud?

4 months. **Explanation:** The development of social and vocalization skills follows a predictable chronological sequence in infants. **Laughing aloud** is a key social-vocal milestone that typically emerges at **4 months** of age. At this stage, the infant transitions from simple cooing to more robust vocal expressions of pleasure and begins to show increased social awareness. * **Option A (2 months):** At this age, the infant reaches the milestone of the **social smile** (responding to a face or voice) and begins **cooing** (vowel-like sounds), but they do not yet have the vocal coordination or social maturity to laugh aloud. * **Option B (4 months):** This is the **correct** milestone for laughing aloud. The child also begins to show excitement by waving arms and can turn their head towards a sound source. * **Option C (6 months):** By 6 months, the child progresses to **monosyllabic babbling** (e.g., "ba," "da," "pa") and starts to recognize familiar faces. Laughing aloud is already well-established by this time. * **Option D (9 months):** At 9 months, the child develops **bisyllabic babbling** (e.g., "mama," "dada" – non-specific) and understands the word "No." **High-Yield Clinical Pearls for NEET-PG:** * **Social Smile:** 2 months (Earliest sign of social interaction). * **Laughs Aloud:** 4 months. * **Mirror Recognition:** 6 months (Smiles at mirror image). * **Stranger Anxiety:** 7–9 months. * **Waves Bye-Bye:** 9 months. * **Specific "Mama/Dada":** 12 months. **Mnemonic:** Remember the "Rule of 2s" for early social/vocal milestones: **2 months** (Smile), **4 months** (Laugh), **6 months** (Babble).

Question 1

An infant presents with features of premature ageing, growth failure, and early-onset atherosclerosis. The child has a characteristic progeroid appearance. Which of the following genes is most commonly associated with this condition? Options:

Accepted Answer

LMNA gene

Answer

WRN gene

Answer

C-KIT gene

Answer

TP53 gene

Question 2

A 19-year-old boy presents with long limbs and hypermobility of joints. Genetic analysis shows a mutation in the FBN1 gene. What is the most likely diagnosis?

Accepted Answer

Marfan syndrome

Answer

Ehlers–Danlos syndrome

Answer

Homocystinuria

Answer

Loeys–Dietz syndrome

Question 3

A 12-year-old girl is being evaluated for pubertal development. On examination, she has early breast development and sparse, thin pubic hair. Based on the Tanner staging diagram provided, what stage does she correspond to?

Accepted Answer

Stage II

Answer

Stage I

Answer

Stage III

Answer

Stage IV

Question 4

Due to persistence of the Moro reflex, a child will have difficulty achieving which of the following developmental milestones?

Accepted Answer

Rolling over

Answer

Neck holding

Answer

Sitting with support

Answer

Sitting without support

Question 5

At what age can a child typically laugh aloud?

Accepted Answer

4 months

Answer

2 months

Answer

6 months

Answer

9 months

Growth and Development — MCQs

Growth and Development — MCQs

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