Familial amyloid polyneuropathy associated with the novel transthyretin variant Arg34Gly

Abstract

We report a 57-year-old man with pathognomonic bilateral vitreo-lenticular amyloid opacities (pseudopodia lentis) in whom a novel transthyretin (TTR) mutation was identified. The patient presented due to bilateral floaters. The vitreous cavities of both eyes showed course, fibrilar opacities attached to the posterior lens surface with pseudopodia. There was a history of bilateral carpal tunnel syndrome. Nerve conduction studies showed upper and lower limb axonal polyneuropathy. Magnetic resonance imaging of the brain and spinal cord, renal and cardiac function were normal. Vitreous and conjunctival biopsies confirmed the diagnosis of TTR-related amyloidosis. Genetic analysis of exon 2 of the TTR gene revealed that the patient was heterozygous for a single nucleotide substitution c.160 A>G, resulting in replacement of arginine with glycine at position 34 of the mature protein (Arg34Gly). Five years later the patient developed increasing sensory and motor neuropathy of both lower limbs, and neovascular glaucoma in one eye. We hypothesize that the reason for his neovascular glaucoma was retinal ischaemia secondary to amyloid retinal vasculopathy.

Keywords::

• ATTR
• neovascular glaucoma
• pseudopodia lentis
• transthyretin amyloid
• vitreous floaters

Declaration of Interest: CERA receives Operational Infrastructure Support from the Victorian Government. This study was supported by the National Health and Medical Research Council Centre for Clinical Research Excellence #529923 – Translational Clinical Research in Major Eye Diseases.