Familial meningocerebrovascular amyloidosis, Hungarian type, with mutant transthyretin (TTR Asp18Gly).

Amyloid deposits in leptomeningeal vessels, subarachnoid, subpial, and subependymal cerebrospinal regions, spinal ganglia, peripheral nerves, and some internal organs (predominantly heart and kidney) characterize a dominantly inherited disease in a Hungarian family. We found four definitely and three probably affected members in this family of 56 persons in four generations. Clinical features in all definitely diseased patients include disturbance of memory, psychomotor deceleration, ataxia, and hearing loss. In most patients there was temporary disorientation, migraine-like headache with vomiting, and tremor. Some patients had nystagmus, pyramidal signs with spastic paraparesis, hallucinations, urinary retention, and obstipation. Single patients had facial tics and sleep disorders. Progressive visual disturbance and clinically manifest polyneuropathy were absent. CSF protein was markedly elevated in all patients. CT showed characteristic symmetric calcification along the sylvian fissure; MRI after contrast administration showed prominent enhancement at the surface of the sylvian fissures, brainstem, and cerebellum. Autopsy data was available in three definitely affected patients and in one unaffected family member. Immunohistochemistry identified the amyloid deposits as of the AF (transthyretin, TTR) type; DNA studies revealed a novel TTR missense mutation at codon 18 (TTR Asp18Gly). According to clinical features, pathologic alterations, and molecular studies, this disease is a novel type of systemic familial amyloidosis with disease manifestation clinically restricted to the CNS. It is similar to the oculoleptomeningeal amyloidoses but can be clinically diagnosed by characteristic CTs and the absence of progressive visual impairment.