Prevalence and histopathological characteristics of corneal stromal dystrophies in Saudi Arabia

Abstract

Purpose:The aim was to determine the frequency and describe the main histopathologic features of corneal stromal dystrophy in Saudi Arabia.Methods:A single-center, retrospective analysis of 193 corneal specimens diagnosed with stromal dystrophy. All samples were retrieved from the Histopathology Department at King Khaled Eye Specialist Hospital over a 10-year period (2002 to December 31, 2011). Cases of stromal dystrophy undergoing keratoplasty were included in the study. Routine histopathologic stains and specific stains were used to determine a diagnosis. The corresponding demographic data and basic clinical/surgical information were collected via chart review.Results:The study sample was comprised of 193 eyes. The final diagnoses were macular corneal dystrophy (MCD) in 180 (93.26%) eyes, granular corneal dystrophy (GCD) in 9 (4.66%) and lattice corneal dystrophy (LCD) in 4 (2.07%) eyes. The mean age at presentation was 27.03 years for MCD, 26.33 years for GCD and 53.75 years for LCD. The interval between diagnosis and surgical intervention was not statistically different between the macular and granular groups (P = 0.141). There was a positive family history for the MCD (37.22%) and GCD (44.44%) groups. All eyes underwent penetrating keratoplasty (PKP) except 10 MCD cases that underwent lamellar keratoplasty. Diffuse stromal deposits were present in 87.2% of MCD corneas and 66.67% of GCD corneas. Seventeen eyes with MCD were misdiagnosed as GCD. None of the LCD cases were clinically identified since all of these cases were diagnosed as corneal scarring. In eyes with MCD that underwent PKP, there was diffuse stromal involvement (in 87.22% eyes) and changes in Descemet's membrane (in 53.5% eyes).Conclusion:This pathological study suggested that MCD was the most common corneal stromal dystrophy that required keratoplasty in Saudi Arabia. Patient with MCD and GCD presented at a significantly younger age than LCD. The clinical diagnosis of MCD is not achieved in all cases likely due to a more severe phenotype in the Saudi population or the presence of corneal scarring that is associated with previous trachoma, which obscures the classical appearance of LCD. We believe that PKP is first-line surgical treatment, especially for MCD because it involves all corneal layers. However, deep stromal involvement and changes in Descemet's membrane in MCD should be considered when selecting the surgical procedure.

Genetic Analysis of CHST6 Gene in Indian Families with Macular Corneal Dystrophy

“…The identified known mutations have been observed among patients from several populations included India Saudi Arabia, Korea, Egypt, Japan, America and France [2,3,1517,18,23]. This additionally supports our findings showed a high degree of mutational heterogeneity among the patients studied.…”

“…Interestingly, we have identified 6 novel mutations in six MCD patients and 11 different known mutations in 38 patients. Previous studies have shown in Saudi Arabian and South Indian population that the prevalence of MCD is high; most probably due to the higher frequency of consanguineous marriage in these ethnic population [2,3]. In our current study, out of 55 families studied, we have also analysed 30 south Indian families with consanguineous marriage.…”

“…It was first described by Groenouw in 1890. Due to high degree of consanguinity in some ethnic population, this disorder is highly prevalent in Saudi Arabia and South Indian population [2,3]. The Clinical manifestations of MCD usually occurs by irregular, focal haze formation that leads to greywhite opacities eventually leading to decreased visual acuity by the fifth decade of life [4].…”

“…The recurrence rate of corneal opacities is more than 40% in macular corneal grafts even after 10 years of Penetrating Keratoplasty (PKP) [7]. CHST6 gene is the only candidate gene so far known in MCD and has been further screened in different ethnic populations across the world [2,3,[8][9][10][11][12][13][14][15][16][17]. It is located on chromosome 16q22 [18,19].…”

Indications and techniques employed for keratoplasty in the Eastern province of Saudi Arabia: 6 years of experience

“…This finding is in line with previously reported rates in Saudi Arabia. 9 , 36 , 37 Recently Alzuhairy et al, 37 have shown that the corneal stromal dystrophy distribution in Saudi Arabia included macular corneal dystrophy in 93.26%, granular corneal dystrophy in 4.66% and lattice corneal dystrophy in 2.07%.…”