Abstract
Purpose::
To report a novel mutation in the TGFBI gene, Met619Lys, associated with a variant of combined granular-lattice corneal dystrophy (CGLCD).
Methods::
Slit lamp examination, photodocumentation and isolation of genomic DNA obtained from buccal mucosal swabs was performed for the proband as well as affected and unaffected relatives. All seventeen exons of the TGFBI gene were amplified and sequenced in the proband. Exon 14 of the TGFBI gene was amplified and sequenced in each of the proband’s family members and in 100 control individuals. Following the performance of bilateral corneal transplantation in the proband, histopathologic examination of the excised corneal buttons was performed.
Results::
Affected individuals demonstrated bilateral, axially distributed needle-like and clumped polymorphic corneal stromal deposits. Coalescence of the stromal deposits in the proband and her siblings produced significant visual impairment, requiring penetrating keartoplasty in the proband and several family members. TGFBI gene screening in the proband demonstrated a novel mutation, Met619Lys, that was also present in all affected family members. Histopathologic examination of the excised corneal buttons revealed stromal deposits that stained with the Congo red and Masson trichrome stains.
Conclusions::
We present a unique corneal dystrophy phenotype associated with the novel Met619Lys mutation in the TGFBI gene. The atypical phenotype, as well as the demonstration of both hyaline and amyloid stromal deposits, previously reported only in combined granular lattice corneal dystrophy associated with the Arg124His mutation in TGFBI, indicate that neither clinical nor histopathologic features may be relied upon to accurately diagnose the corneal dystrophies.
Keywords: mutations • genetics • cornea: basic science