Classic lattice corneal dystrophy associated with monoclonal gammopathy after exclusion of a TGFBI mutation

PURPOSE: The purpose of this study was to report the association of phenotypic features characteristic of lattice corneal dystrophy (LCD) with a monoclonal gammopathy of undetermined significance (MGUS) after exclusion of a coding region mutation in transforming growth factor beta-induced (TGFBI) gene. DESIGN: Case report. METHODS: Slit-lamp examination and collection of DNA for TGFBI screening were performed. A systemic evaluation was also performed to evaluate for conditions associated with systemic amyloidosis. RESULTS: A 65-year-old man demonstrated bilateral linear branching corneal stromal opacities characteristic of classic LCD. No mutations were found in any of the 17 exons of TGFBI or in the intron-exon boundary regions. Four previously described single nucleotide polymorphisms were identified: c.698C>G (p.Leu217Leu; rs1442), c.1028A>G (p.Val327Val; rs1054124), c.1416C>T (p.Leu472Leu; rs1133170), and c.1667T>C (p.Phe540Phe; rs4669). Serum protein electrophoresis revealed the presence of a monoclonal spike, and based on the results of additional investigations, the patient was diagnosed with MGUS. CONCLUSIONS: Although the presence of bilateral thin branching lattice lines in the corneal stroma is characteristic of classic LCD, this distinctive phenotype may not be associated with a TGFBI coding region mutation but instead with a myeloproliferative disorder such as MGUS. Therefore, appropriate genetic and serologic testing should be performed in patients with a late-onset LCD phenotype in the absence of a positive family history.