Hereditary leptomeningeal transthyretin amyloidosis with heterozygous TTR mutation: a case report and literature review.

Objective: This study aimed to characterize the clinical and neuroimaging features of hereditary leptomeningeal transthyretin amyloidosis (hATTR-LA), a dominant inheritance disorder caused by a heterozygous TTR gene mutation.

Methods: A comprehensive retrospective evaluation was conducted, incorporating detailed clinical records, multimodal neuroimaging findings, and a systematic review of the literature to contextualize the observations.

Results: The patient was a 55-year-old male who presented with chronic central nervous system symptoms, including sensory-motor peripheral neuropathy and progressive visual impairment. Cerebrospinal fluid analysis revealed elevated protein levels. Neuroimaging showed progressive leptomeningeal hyperdensity on CT and characteristic linear thickening with enhancement of the leptomeninges on MRI, involving both cerebral and spinal regions. Genetic testing confirmed the diagnosis by identifying a heterozygous c.265T > C (p.Y89H) pathogenic variant in exon 3 of the TTR gene, classified as pathogenic according to ACMG guidelines.

Conclusion: Multimodal imaging provides valuable, non-invasive insights for diagnosing hATTR-LA, enhancing diagnostic accuracy and informing clinical management of this rare condition.