Transthyretin amyloidosis (aTTR) initially described as a rare disease, became the most serious hereditary polyneuropathy of adult onset and family screening has made it possible to identify and follow up many asymptomatic patients and carriers of the mutation in the TTR gene.

Considered as a systemic disease with involvement of target organs (the heart, the eye, the kidney and peripheral nervous system), it seems to be more complex for neurologists according to recent publications raising the issue of central nervous system involvement.

Indeed, TTR amyloid deposits seem to be correlated with the duration of the disease. These deposits can cause cortical damage by different mechanisms: direct TTR toxicity or as a result of pathology related to cerebral amyloid angiopathy (intraparenchymal or subarachnoid hematomas, small infarcts, hemosiderin). A small number of mutations in the TTR gene cause a rare phenotype of systemic amyloidosis, the oculoleptomeningeal form, characterized by clinical neurological symptoms: progressive dementia, epilepsy, ataxia, spastic paraparesis, stroke-like episodes.

Hypothesis of the work: the central nervous system involvement is probably underestimated on the radiological description in patients with TTR mutation.

Inclusion Criteria:

• patients followed at the University Hospital of Nîmes between 2017 and 2021 for a TTR neuropathy with proven mutation, having benefited from a brain MRI.

Exclusion Criteria:

• Patients without TTR neuropathy with proven mutation, or who did not have a brain MRI.

Patients followed at the University Hospital of Nîmes between 2017 and 2021 for a TTR neuropathy with proven mutation, having benefited from a brain MRI.