Lattice corneal dystrophy type II associated with familial amyloid polyneuropathy type IV.

Background: Finnish-type familial amyloidosis (FAP-IV) is an autosomal, dominantly inherited disorder characterized by progressive polyneuropathy and lattice corneal dystrophy type II. The vast majority of families with this disorder originated from Finland. Only two families, in neighboring districts, have been reported in Japan previously.
Methods: The authors report two additional Japanese patients with FAF-IV. The proband, a 70-year-old man, had decreased perspiration and abnormal facial muscle movement. Results of neurologic examination showed bilateral facial and hypoglossal nerve palsies, and an autonomic disturbance, including orthostatic hypotension and dysfunction of perspiration. Histochemical, immunohistological, and DNA studies confirmed the diagnosis of FAP-IV.
Results: Results of ophthalmologic examination showed asymptomatic lattice corneal dystrophy of both eyes, but the appearance of the cornea was different from that described in the patients from Finland. Lattice lines in the authors' patient were very fine, short, and glassy and could be observed with indirect retroillumination, but might be missed with direct illumination by the slit-lamp microscope. The proband's younger half-sister, a 68-year-old woman, showed clinical findings and laboratory data similar to those of the proband.
Conclusion: The authors report two Japanese patients with lattice corneal dystrophy type II related to FAP-IV. This is the third Japanese family with this disorder, and there is no familial relationship to the two previously reported families in Japan.