Mutation analysis of the TGFBI gene in Vietnamese with granular and Avellino corneal dystrophy.
OBJECTIVE
Mutations of the human transforming growth factor beta-induced gene (TGFBI) were reported to cause granular (GCD) and Avellino (ACD) corneal dystrophy in various nationalities. In this study we examined the TGFBI gene in a Vietnamese population with GCD and ACD.


METHODS
Eight unrelated Vietnamese families, including 20 affected and 24 unaffected individuals, were examined; 50 normal Vietnamese individuals were used as controls. Genomic DNA was extracted from peripheral blood leukocytes. The TGFBI gene was analyzed using the polymerase chain reaction and direct sequencing. The corneal button was studied.


RESULTS
Slit-lamp examination revealed typical features of GCD in most cases. A few features of ACD and a patient with an atypical form of GCD were also seen. Histopathological analysis of a GCD cornea showed deposits that stained bright red with Masson trichrome. Sequencing revealed three distinct mutations: R555W in six families, R124H in one family, and D123H in another.


CONCLUSIONS
R555W and R124H mutations were co-segregated with the disease phenotype and thus caused GCD and ACD, respectively, in the families studied. The R555W detected in six of the eight families indicates that the GCD phenotype may be the most common in Vietnamese individuals, unlike in other Asians (Japanese and Korean), where ACD is most common (>90%). The D123H mutation may cause an atypical variant of GCD.
Cung
Le Xuan
le X
National Institute of Ophthalmology, Hanoi, Vietnam.
Ha
Nguyen Thanh
NT
Chau
Hoang Minh
HM
Thanh
Ton Kim
TK
Fujiki
Keiko
K
Murakami
Akira
A
Hiratsuka
Yoshimune
Y
Kanai
Atsushi
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D003317:Corneal Dystrophies, Hereditary / Q000208:ethnology / Q000235:genetics*; D004252:DNA Mutational Analysis; D016326:Extracellular Matrix Proteins / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020125:Mutation, Missense; D010375:Pedigree; D016133:Polymerase Chain Reaction; D016212:Transforming Growth Factor beta / Q000235:genetics; D014744:Vietnam / Q000453:epidemiology; D000099222:betaIG-H3 Protein
D016326:Extracellular Matrix Proteins; D016212:Transforming Growth Factor beta; D000099222:betaIG-H3 Protein