Identification of mutations in the SLC4A11 gene in patients with recessive congenital hereditary endothelial dystrophy.

OBJECTIVE To identify Solute Carrier family 4 (sodium borate cotransporter) member 11 (SLC4A11) gene mutations associated with autosomal recessive congenital hereditary endothelial dystrophy (CHED2). METHODS DNA extraction from blood, polymerase chain reaction amplification, and direct sequencing of all the exons of the SLC4A11 gene were performed for 26 affected members of 20 unrelated families with CHED2. RESULTS Of 10 mutations observed, 6 were novel, 1 of which involves a complete deletion of exon 6, identified for the first time, to our knowledge, in SLC4A11. The mutations cosegregated with the disease phenotype and were absent in 200 ethnically matched control chromosomes analyzed. CONCLUSIONS This study increases the number of SLC4A11 gene mutations and confirms the role of this gene in causing CHED2. Clinical examination did not reveal any considerable variability in disease expressivity in patients carrying SLC4A11 mutations. Extensive linkage analysis may reveal the modifier genes involved in causing CHED2 in the SLC4A11 mutations unidentified in 9 families. CLINICAL RELEVANCE In India, there is a high frequency of CHED2, possibly related to consanguineous marriages. Counseling could be provided to explain the drawbacks of consanguineous marriages to assist in reducing this devastating disorder.