[Autosomal dominant inherited corneal dystrophies associated with TGFBI mutation].
BACKGROUND
Mutations of the transforming growth factor beta-induced (TGFBI) gene whose product is called keratoepithelin (KE) have been identified in 4 major autosomal dominantly inherited corneal dystrophies. The purpose of this study was to identify the mutations in Japanese patients with these dystrophies, and to investigate the nature of corneal deposits.


METHODS
Mutations of the TGFBI gene were screened by polymerase chain reaction (PCR) followed by direct sequencing of the PCR products in Japanese patients clinically diagnosed as having granular corneal dystrophy, Avellino corneal dystrophy, lattice corneal dystrophy, and Reis-Bücklers' dystrophy. Corneal specimens obtained from corneal transplants were analyzed by histochemistry (Masson trichrome and Congo red stains), immunohistochemistry, and western blotting using anti KE antibody. I reviewed papers about TGFBI gene mutations previously published.


RESULTS
The genotype/phenotype relationship of corneal dystrophies associated with mutations of the TGFBI gene is markedly evident. Avellino corneal dystrophy associated with the R 124 H mutation was the most common form of corneal stromal dystrophy in Japan. In Japan this dystrophy has been called granular corneal dystrophy up to now. Thiel-Behnke dystrophy (R 555 Q) has been also misdiagnosed as Reis-Bücklers' dystrophy. The original Reis-Bücklers' dystrophy is associated with R 124 L, which is compatible with superficial granular corneal dystrophy. Corneal deposits were associated with TGFBI products whose sizes were specific for their mutations.


CONCLUSIONS
Mutations of the gene resulted in different types of KE aggregation accompanied with characteristic changes of processing and metabolism. The classification of these diseases according to genetic pathogenesis may be more appropriate than the use of clinical or histological findings.
Mashima
Y
Y
Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
Yamada
M
M
Oguchi
Y
Y
D003317:Corneal Dystrophies, Hereditary / Q000145:classification / Q000235:genetics* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D009154:Mutation / Q000235:genetics*; D016212:Transforming Growth Factor beta / Q000235:genetics*; D053773:Transforming Growth Factor beta1
C508960:TGFB1 protein, human; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1