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KEY WORDS: familial amyloidotic polyneuropathy, vitreous amyloidosis, systemic symptoms
ABBREVIATIONS: FAP = familial amyloidotic polyneuropathy; TTR = transthyretin; ATTR = amylodogenic transthyretin; Val30Met = substitution of methionine for valine at position 30; IOP = intraocular pressure
Abstract
We describe a case of vitreous amyloidosis without systemic symptoms in familial amyloidotic polyneuropathy (FAP) associated with Val30Met transthyretin mutation. A healthy 74-year-old woman noticed left blurred vision and floaters in 1992. Severe vitreous opacities were identified in the left eye. The patient displayed no systemic symptoms, and Congo red staining of the biopsy samples of the stomach and duodenum revealed no amyloid deposition. A diagnosis of FAP was confirmed following genetic investigation. Vitrectomy and cataract surgery was performed with intraocular lens implantation in April 1998. Histopathological examination of the vitreous material revealed amyloid fibrils. Intraocular pressure (IOP) gradually elevated and cupping of the optic disc enlarged. Trabeculectomy was performed in February 2000, but postoperative IOP was again elevated and a needling procedure was performed in March 2000. No postoperative recurrence of vitreous opacity has been reported and IOP has remained well controlled. In the present case, ocular manifestations were the only symptoms of FAP and systemic symptoms have not developed, after more than 12 years. FAP should be suspected as the cause in cases of vitreous opacities in patients from areas with endemic foci of FAP.
Introduction
Familial amyloidotic polyneuropathy (FAP) is an autosomal dominant inherited disorder characterized by systemic accumulation of amyloid fibrils in peripheral nerves and other organs. The most common type of FAP is caused by a mutated transthyretin (Val30Met) in which a methioninc residue is substituted for the valinc normally at position 30. Patients usually start to show sensory dominant polyneuropathy or autonomie dysfunction as an initial symptom1. However, other clinical manifestations can suggest the diagnosis of FAP. Ocular manifestations represent one of the most important symptoms during the course of FAP ATTR Val30Met2. Vitreous opacity is one of the most...