[Autosomal dominant granular corneal dystrophy caused by a TGFBI gene mutation in a Mexican family].
OBJECTIVE
To describe the clinical data and the results of molecular analyses of the TGFBI gene in a patient with classic granular stromal corneal dystrophy (type I).


METHODS
A female patient aged 60-years complaining of a long-standing decrease of visual acuity bilaterally associated with photophobia and foreign body sensation, underwent a complete ophthalmologic examination. Molecular analyses of DNA from the patient and from an affected brother included PCR amplification of exons 4, 11, 12, and 14 of the TGFBI gene and direct automated sequencing of the PCR products.


RESULTS
The affected patient showed a pattern of corneal stromal lesions that was compatible with a diagnosis of classic granular dystrophy. No involvement of other corneal layers was evident. Molecular analysis disclosed a point mutation in exon 14 of the TGFBI gene which consisted of an adenine to guanine change at nucleotide position 1924, predicting a substitution of arginine instead of histidine at residue 626 of the TGFBI protein (H626R). An identical mutation was detected in DNA from her affected brother.


CONCLUSIONS
This is the first time that a case of stromal granular dystrophy has been demonstrated to be caused by the H626R mutation, a molecular defect classically detected in the phenotypically distinct lattice corneal dystrophy. Our data indicate that the same molecular defects in the TGFBI gene lead to different phenotypes in stromal dystrophies, thus expanding the genotypic-phenotypic spectrum in this group of corneal diseases.
Zenteno
J C
JC
Instituto de Oftalmología Conde de Valenciana, México D.F., México. jczenteno@salud.gob.mx
Santacruz-Valdés
C
C
Ramírez-Miranda
A
A
D003317:Corneal Dystrophies, Hereditary / Q000235:genetics*; D016326:Extracellular Matrix Proteins / Q000235:genetics*; D005260:Female; D006801:Humans; D008800:Mexico; D008875:Middle Aged; D009154:Mutation; D010375:Pedigree; D016212:Transforming Growth Factor beta / Q000235:genetics*; D000099222:betaIG-H3 Protein
D016326:Extracellular Matrix Proteins; D016212:Transforming Growth Factor beta; D000099222:betaIG-H3 Protein