Macular corneal dystrophy: mutational spectrum in German patients, novel mutations and therapeutic options.

INTRODUCTION: The objective of this study was to investigate genotype-phenotype correlations, the consequences for surgical treatment, and the therapeutical options in patients with macular corneal dystrophy (MCD).

MATERIAL AND METHODS: We investigated MCD genotype by using polymerase chain reaction followed by direct sequencing in one family and four patients with MCD. Results were confirmed by restriction analysis. Clinical phenotypes, histopathological findings, and therapeutical proceedings of each patient were reported and compared with the molecular genetic results.

RESULTS: Five mutations, four missense mutations, and one frameshift mutation, from which three were novel, and one single-nucleotide polymorphism, were identified within the coding region of the CHST6 gene. In three patients, two with a homozygous mutation within the start codon (Met1Leu) and one with a heterozygous mutation (Leu200Arg) and a polymorphism (Arg162Gly), with irregular corneal surface and recurrent erosions a phototherapeutic keratectomy lead to a transient success. An additional fitting of rigid gas permeable contact lenses in one patient could further improve irregular astigmatism. In two patients, one with a frameshift mutation (1734_1735delTG; Arg211Gln) and one with two compound heterozygous mutations (Leu200Arg; Leu173Phe) and an additional polymorphism (Arg162Gly) a penetrating keratoplasty improved BCVA without any recurrence of the opacities within the follow-up time.

DISCUSSION: Different genotypes imply several phenotypes, which influence therapeutical proceedings in MCD patients. Our study shows the wide range of diagnostic findings and therapeutical options in patients suffering from macular corneal dystrophy depending on the genotype.