Absence of phenotype-genotype correlation of patients expressing mutations in the SLC4A11 gene.
OBJECTIVE
The purposes of this study were to describe the clinical characteristics of corneal patients with mutations in the SLC4A11 gene and to determine if these characteristics could be correlated with specific genetic mutations.


METHODS
A retrospective case series review was conducted. Baseline demographic data, including gender, age at diagnosis of congenital hereditary endothelial dystrophy, family history, and pedigree information, were obtained. Information from clinical examination, including intraocular pressure, ultrasonic pachymetry, best spectacle-corrected visual acuity, axial length, and slit-lamp biomicroscopic evaluation, including corneal diameter and fundus examination, were also documented from the notes. History of corneal surgery was also recorded. Hearing loss was assessed by audiometry. Genetic analysis was performed by polymerase chain reaction amplification and sequencing.


RESULTS
Seven patients were identified. Four of the seven had associated hearing loss; all of the patients had undergone or were awaiting penetrating keratoplasty to one or both eyes. No correlation could be reached between the ocular phenotype and the gene mutation in this small sample. Individuals with the same mutation had different degrees of hearing loss within their respective families.


CONCLUSIONS
Corneal endothelial cells are more vulnerable to defects in the functional activity of SLC4A11 than cells of the striae vascularis of the inner ear. Both congenital hereditary endothelial dystrophy 2 and Harboyan syndrome have similar ocular phenotypes, ie, diffuse bilateral corneal edema present at birth or within the neonatal period; hence, audiometry must be performed to differentiate the two conditions.
Mehta
Jodhbir Singh
JS
Singapore National Eye Centre, Singapore. jodmehta@gmail.com
Hemadevi
Boomiraj
B
Vithana
Eranga N
EN
Arunkumar
Jambulingam
J
Srinivasan
Muthaiah
M
Prajna
Venkatesh
V
Tan
Donald T
DT
Aung
Tin
T
Sundaresan
Periasamy
P
D000293:Adolescent; D027321:Anion Transport Proteins / Q000235:genetics*; D017920:Antiporters / Q000235:genetics*; D001299:Audiometry; D002648:Child; D002675:Child, Preschool; D003317:Corneal Dystrophies, Hereditary / Q000175:diagnosis* / Q000235:genetics* / Q000601:surgery; D004728:Endothelium, Corneal / Q000002:abnormalities* / Q000473:pathology; D005260:Female; D005838:Genotype; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000235:genetics*; D006801:Humans; D015948:Keratoplasty, Penetrating; D008297:Male; D009154:Mutation; D010375:Pedigree; D010641:Phenotype; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055815:Young Adult
D027321:Anion Transport Proteins; D017920:Antiporters; C425809:SLC4A11 protein, human