Mutations in the membrane component, chromosome 1, surface marker 1 (M1S1) gene in gelatinous drop-like corneal dystrophy.

PURPOSE: To report mutations in the membrane component, chromosome 1, surface marker 1 ( M1S1) gene in two members of the same family who showed symptoms of gelatinous drop-like corneal dystrophy (GDLD).

METHODS

DNA was extracted from leukocytes of peripheral blood of the two affected members of the family and from controls, and the coding region of M1S1 was amplified by polymerase chain reaction (PCR). The PCR products were analyzed by direct sequencing. Normal and mutant M1S1 expression vectors were constructed and transfected into CHO cells to identify the cellular location of the gene products.

RESULTS

The affected members had compound heterozygous mutations consisting of a nonsense change at codon 84 (K84X) and a missense mutation resulting in a substitution of arginine for cysteine at codon 108 (C108R). Neither of these mutations was found in the 50 controls. Protein expression analysis showed that the C108R product was distributed diffusely in the cytoplasm, whereas the normal gene product accumulated at cell-to-cell adhesion borders.

CONCLUSION

These data indicate that the K84X and C108R mutations in M1S1 cause GDLD.