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Difficulty: HardPediatric Neurologic Disorders

An 18-month-old girl is brought to the pediatric neurology clinic by her parents due to recurrent episodes of rhythmic jerking of her right arm and leg. The episodes last about 2 minutes and have occurred three times over the past month. Her past medical history is notable for a large, unilateral, dark red, non-blanching macular lesion over the left side of her face, involving the forehead and upper eyelid, which has been present since birth. Her parents are very anxious and express concern regarding her overall development. They report that she walks independently and has a vocabulary of about 15 words, but they are deeply worried because she cannot yet run, kick a ball, or combine two words into a phrase. Which of the following statements regarding this patient's diagnosis and management are accurate? (Select all that apply)

  1. The underlying pathophysiology involves a somatic activating mutation in the GNAQ gene, resulting in capillary-venous malformations.Answer
  2. She is at high risk for ipsilateral glaucoma and requires a comprehensive ophthalmologic evaluation.Answer
  3. C
    Her inability to combine two words into a phrase at 18 months represents a significant language delay requiring immediate speech therapy.
  4. D
    Her gross motor skills are currently severely delayed, as independent running and kicking a ball should have been achieved by 12 months.
  5. E
    The facial lesion is indicative of a disseminated congenital viral infection and requires prompt initiation of empiric systemic antiviral therapy.

Answer

The accurate statements are that the condition is caused by a somatic activating mutation in the GNAQ gene, and the patient requires comprehensive ophthalmologic evaluation due to high glaucoma risk.
The correct statements accurately reflect the underlying genetics and complications of Sturge-Weber syndrome. The syndrome is uniquely caused by a non-inherited, somatic activating mutation in the GNAQ gene, which disrupts vascular development. The resulting vascular malformations frequently extend to the eye, placing the patient at a significant risk for early-onset ipsilateral glaucoma that requires vigilant screening.

Step-by-Step Solution

1
Identify the primary clinical syndrome based on the presenting physical signs.
The presence of a congenital facial port-wine stain in the V1/V2 distribution coupled with focal motor seizures points directly to Sturge-Weber syndrome.
Recognizing the classic triad of facial capillary malformation, leptomeningeal angiomatosis (causing seizures), and ocular involvement is the first step to establishing the diagnosis.
2
Determine the etiology and standard complications of the identified syndrome.
Sturge-Weber syndrome is caused by a somatic mosaic mutation in GNAQ and carries a very high risk of early-onset glaucoma in the ipsilateral eye.
This confirms the accuracy of the statements regarding genetics and ophthalmologic screening.
3
Evaluate the parents' concerns regarding the child's developmental milestones.
The patient can walk and speak 15 words. She cannot run, kick, or use 2-word phrases.
It is critical to distinguish between actual developmental delay, which can occur in Sturge-Weber syndrome, and age-appropriate development.
4
Compare the patient's abilities to standard pediatric milestone charts for an 18-month-old.
Walking and a 15-word vocabulary are completely normal for 18 months. Running, kicking, and 2-word phrases are 24-month milestones.
This rules out the distractors that inaccurately classify the patient as having severe motor or language delays.

Key Concept

Sturge-Weber syndrome is a sporadic neurocutaneous disorder caused by a somatic GNAQ mutation, characterized by a port-wine stain, leptomeningeal angiomatosis, and high glaucoma risk. Furthermore, accurately differentiating between 18-month milestones (walking, 10-25 words) and 24-month milestones (running, kicking, 2-word phrases) is essential in pediatric assessment.
Estimated Time:1m 30s
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Topics

Pediatric Neurologic Disorders

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