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Fabry Disease – Family Screening — SCE Neurology MCQ

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ModerateNeurogeneticsFabry Disease – Family ScreeningSCE Neurology

A 45-year-old man has genetically confirmed Fabry disease. His 23-year-old sister has no symptoms and normal alpha-galactosidase A activity. What is the most appropriate cascade-testing strategy for her?

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Correct answer: C — Targeted molecular testing for the familial GLA pathogenic variant

Female heterozygotes can have normal or near-normal alpha-galactosidase A activity because of X-chromosome inactivation. Targeted testing for the known familial GLA variant is the appropriate cascade test; enzyme testing is most reliable for affected males. MRI and renal biopsy may contribute to phenotypic assessment after diagnosis but cannot replace molecular testing.

Reference: NHS Genomic Medicine Service: Fabry disease: https://southeastgenomics.nhs.uk/tool/fabry-disease/