Ocular involvement in familial amyloid polyneuropathy

Familial amyloid polyneuropathy (FAP) or transthyretin (TTR) amyloid polyneuropathy is a progressive sensorimotor and autonomic neuropathy of adult onset, which is transmitted as an autosomal dominant trait. In addition to neurologic symptoms, FAP may be associated with weight loss, cardiac and renal failure and ocular complications. FAP is a devastating disease, causing death within 10years after the first symptoms. The TTR Val30Met mutation is the most common of more than 100 amyloidogenic mutations identified worldwide. Liver transplantation (LT) is currently the only treatment for preventing synthesis of the amyloidogenic variants of TTR. LT can halt progression of the neuropathy in up to 70% of cases and doubles the overall median survival of young Val30Met patients. Oral administration of tafamidis, which prevents deposition of mutated TTR, is now available to delay neurologic complications in early stages of the disease. Ocular manifestations of FAP are frequent and mainly include keratoconjunctivitis sicca, secondary glaucoma, vitreous deposits and pupillary abnormalities. Retinal and choroidal vascular abnormalities are more rare. Since ocular TTR is synthesized, at least in part, in the retinal pigment epithelium, LT does not influence the course of ocular involvement. The effects of tafamidis on the latter are still unknown. Because LT and symptomatic treatments greatly improve life expectancy of patients with FAP, ocular involvement is becoming a more frequent challenge to address. This review summarizes the pathophysiology, clinical findings and possible treatments of ocular manifestations of FAP.