LAUSR

Meretoja syndrome (familial amyloid polyneuropathy type IV) is a rare disease of the amyloidal system inherited in a dominant autosomal manner, and was first described in 1969.1 The largest affected population is found in Finland, where approximately 400 to 600 cases have been described. This disease is rare in other countries and only 15 cases have been described elsewhere, mainly in Japan, Europe, Iran, and the United States.2-7 This is the first described syndrome caused by a point mutation in codon 640 (previously 654) of the gelsolin gene (named c.640G > A or c.640G > T; chromosome 9q32-34) that results in the substitution of asparagine by aspartate at residue 187 (Asn-187). Gelsolin is an actin-modulating protein synthesized in most human tissues. Variant gelsolin expression causes an anomalous degradation product to form and manifests phenotypically as extracellular deposition of gelsolin amyloid, and causes other consequences in gelsolin metabolism and function.2,3,7,8 Normally, gelsolin permits rapid migration of cells involved in wound healing, hemostasis, and the inflammatory process9 and prevents the toxic effects of actin. Mutations of the gelsolin gene cause familial amyloid polyneuropathy type IV.10,11 Clinical manifestations are late-onset, commonly appearing between the thirties and fifties, and slow progress. The earliest and most typical characteristic is type II lattice corneal dystrophy, which is no longer regarded as a dystrophy because it is caused by systemic amyloidosis. Other signs are polyneuropathy, dermatochalasis, open-angle glaucoma, bilateral progressive facial paralysis, cutis laxa, skin fragility with ecchymosis, facial mask, diffuse hair loss, dry skin, bilateral carpal tunnel syndrome, nephrotic syndrome, and cardiomyopathy with conduction alterations and early aging.3,4,6-8,11-14 Corneal deposit distribution is pathognomonic, and diagnosis can be made by histological analysis after corneal transplantation or molecular diagnostic tests.15 No specific treatment for Meretoja syndrome is currently available. Therefore, correct diagnosis only permits treatment of symptoms, including ophthalmologic, neurological, dermatological, cardiac, and renal manifestations. Plastic surgery can improve quality of life and self-esteem in affected patients.2