Which of the following parts is missing or underdeveloped in the Aicardi syndrome?

PGICH Noida NO-2025

Pathology & Genetics

Easy

Appeared in: PGICH Noida NO-2025

Explanation

Aicardi syndrome is a rare genetic disorder defined by a classic triad of symptoms.
The primary and defining brain malformation in this syndrome is the partial or complete absence (agenesis) of the corpus callosum.
The corpus callosum is a large bundle of nerve fibers responsible for communication between the left and right cerebral hemispheres.
The other two features of the triad are infantile spasms (a type of seizure) and chorioretinal lacunae (lesions in the eye's retina).

Option A: This is the large opening at the base of the skull for the spinal cord. While abnormalities of the posterior fossa (like Chiari malformation) involve this opening, it is not the primary defect in Aicardi syndrome.
Option C: This is the lower part of the brainstem controlling vital functions. While neurological function is severely impaired in Aicardi syndrome, the medulla itself is not the primary underdeveloped structure.
Option D: This is a small fold of the dura mater that separates the two hemispheres of the cerebellum. It is anatomically and functionally distinct from the corpus callosum, which connects the cerebral hemispheres.

Clinical Relevance

Nursing practice connection: Knowing Pathophysiology and clinical features of Aicardi Syndrome helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses caring for infants with Aicardi syndrome must be skilled in managing difficult-to-control seizures (infantile spasms) and providing respiratory and feeding support due to severe developmental delays.
Family support is crucial. Nurses play a key role in educating the family about the condition's poor prognosis, managing expectations, and connecting them with support groups and palliative care resources.
What if? If an infant presents with infantile spasms but an MRI shows a normal corpus callosum, the diagnosis is not Aicardi syndrome. The nurse should anticipate further investigations for other causes, such as tuberous sclerosis or perinatal brain injury.

How to Approach the Question

Identify the core concept: The question asks for a specific anatomical defect associated with 'Aicardi syndrome.'
This is a factual recall question. Access your knowledge of congenital neurological disorders.
Recall the classic triad of Aicardi syndrome: 1) Agenesis of the corpus callosum, 2) Infantile spasms, and 3) Chorioretinal lacunae.
Scan the options to find one of these key features.
The 'Corpus callosum' is listed as an option and is the defining brain malformation in the triad.
Eliminate the other options as they relate to different anatomical parts of the brain and skull not primarily associated with this specific syndrome.

Concept Tested & Keywords

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E6 Nelson Textbook of Pediatrics(2024) — Volume 2 pp. 1380-1382, 1382-1384

E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed p. 1245-1247