A child presents with chronic progressive ataxia, and on eye examination, conjunctival telangiectasias are seen. MRI brain shows characteristic findings. What is the most likely diagnosis?
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Patients with Ataxia-Telangiectasia are exquisitely sensitive to ionizing radiation (due to defective DNA repair). X-rays and CT scans should be minimized to avoid inducing severe cellular damage and triggering secondary malignancies.
NBIA (Neurodegeneration with brain iron accumulation)
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The Correct Option isB
Solution and Explanation
Concept:
The clinical triad of a child presenting with progressive cerebellar ataxia and prominent oculocutaneous vascular anomalies (conjunctival telangiectasias) is universally the textbook description of the systemic neurocutaneous syndrome Ataxia-Telangiectasia (Louis-Bar syndrome).
However, the options provided focus on specific radiological/pathological terms, with the official key pointing to "Cerebral telangiectasia". Explanation: • Ataxia-Telangiectasia is an autosomal recessive disorder caused by mutations in the ATM gene, which is critical for DNA repair.
• The disease is characterized by profound cerebellar degeneration (causing progressive ataxia starting in toddlerhood), immunodeficiency (recurrent sinopulmonary infections), high risk of malignancies, and prominent dilated blood vessels (telangiectasias) on the bulbar conjunctiva and sun-exposed skin.
• The provided image likely demonstrates a capillary telangiectasia in the brain. Capillary telangiectasias are small, benign vascular malformations consisting of dilated capillaries interspersed with normal brain parenchyma. They frequently occur in the pons or cerebellum.
• The combination of the clinical vignette strongly pointing toward the syndrome Ataxia-Telangiectasia and the direct naming of the vascular lesion aligns with the answer key's selection of "Cerebral telangiectasia".
• Option (A), Cavernous angioma, is a different vascular malformation (a tight cluster of dilated, thin-walled sinusoidal vessels without intervening normal brain tissue) and often causes seizures or focal hemorrhages, not classic progressive bilateral ataxia with conjunctival lesions.
• Option (C), Fahr syndrome, involves widespread bilateral calcification of the basal ganglia, not telangiectasias.
• Option (D), NBIA, presents with extrapyramidal symptoms (dystonia, parkinsonism) and the "eye of the tiger" sign on MRI, unrelated to conjunctival telangiectasias. Final answer:
The clinical scenario and key correspond to Cerebral telangiectasia, consistent with the hallmark vascular lesions of Ataxia-Telangiectasia.
