Exome capture reveals ZNF423 and CEP164 mutations, linking renal ciliopathies to DNA damage response signaling

Nephronophthisis-related ciliopathies (NPHP-RC) are degenerative recessive diseases that affect kidney, retina, and brain. Genetic defects in NPHP gene products that localize to cilia and centrosomes defined them as "ciliopathies." However, disease mechanisms remain poorly understood. Here, we identify by whole-exome resequencing, mutations of MRE11, ZNF423, and CEP164 as causing NPHP-RC. All three genes function within the DNA damage response (DDR) pathway. We demonstrate that, upon induced DNA damage, the NPHP-RC proteins ZNF423, CEP164, and NPHP10 colocalize to nuclear foci positive for TIP60, known to activate ATM at sites of DNA damage. We show that knockdown of CEP164 or ZNF423 causes sensitivity to DNA damaging agents and that cep164 knockdown in zebrafish results in dysregulated DDR and an NPHP-RC phenotype. Our findings link degenerative diseases of the kidney and retina, disorders of increasing prevalence, to mechanisms of DDR.

Ocular complications of Rift Valley fever outbreak in Saudi Arabia

OBJECTIVE

To report ocular complications of Rift Valley fever (RVF) during its first reported outbreak in southwest Saudi Arabia in autumn 2000.

DESIGN

Cross-sectional study of patients in a referral hospital.

PARTICIPANTS

One hundred forty-three consecutive patients with confirmed RVF serologic test results and ocular lesions were enrolled in the study.

METHODS

Hospitalized patients (n = 30) and outpatients (n = 113) with clinical symptoms consistent with RVF, positive RVF serologic test results, and ocular abnormalities were studied. Ophthalmologic examinations, including fundus photography and fluorescein angiography, were performed. Patients were followed up at regular intervals to determine the prognosis and outcome of identified ocular abnormalities.

MAIN OUTCOME MEASURES

Visual acuity at initial presentation and course of anterior and posterior segment complications.

RESULTS

Among 143 patients (78% males; mean age, 53.2 years), 212 eyes were affected, comprising 47 eyes in 30 inpatients and 165 eyes in 113 outpatients. The mean interval between the onset of RVF and visual symptoms ranged from 4 to 15 days (mean, 8.8 days). Macular or paramacular retinitis was identified in all the affected eyes (n = 212) at the time of initial assessment. Lesions included retinal hemorrhages (40%), vitreous reactions (26%), optic disc edema (15%), and retinal vasculitis (7%). Anterior uveitis was present in 31% of outpatients. Fluorescein angiography of the retinitis showed early hypofluorescence with late staining of retinal lesions and blood vessels. Initial visual acuity was less than 20/200 in 80% of eyes in the outpatient group; their vision improved, deteriorated, or remained the same in 13%, 15%, or 72%, respectively. Evaluation at the last follow-up showed macular (60%) or paramacular (9%) scarring, vascular occlusion (23%), and optic atrophy (20%) in the outpatient group.

CONCLUSIONS

Rift Valley fever was associated with major ocular morbidity. Ocular manifestations of RVF occurred with a relatively higher frequency than reported up to now and were not limited to severe infections. Rift Valley fever affects the uvea and posterior chorioretinal area and is associated with permanent visual loss resulting from macular and paramacular scarring, vascular occlusion, and optic atrophy. The study demonstrated for the first time that transient nongranulomatous anterior uveitis is associated with RVF.

Corneal ectasia in vernal keratoconjunctivitis

The type of corneal ectasia, the presence of breaks in Descemet's membrane, and the success with contact lens wear or penetrating keratoplasty were studied in 61 patients with corneal ectasia and vernal keratoconjunctivitis. There were 53 patients with keratoconus, 5 with pellucid marginal corneal degeneration, 2 with keratoglobus, and 1 with superior corneal thinning. The high rate of hydrops and the corneal ectasia itself may be related to excessive eye rubbing. Success with contact lens wear or penetrating keratoplasty in vernal keratoconjunctivitis patients with keratoconus is less than in patients with keratoconus alone.

Incidence, clinical features, causative organisms, and visual outcomes of delayed-onset pseudophakic endophthalmitis

PURPOSE

To report the incidence, clinical features, causative organisms, and visual outcomes associated with delayed-onset pseudophakic endophthalmitis.

METHODS

We retrospectively reviewed the clinical records and microbiology files of all patients with culture-proven endophthalmitis that was present 6 weeks or more after cataract extraction and posterior chamber intraocular lens (IOL) implantation who were treated at King Khaled Eye Specialist Hospital (KKESH) during a 10-year period.

RESULTS

From January 1997 through December 2006, 17 patients with culture-proven, delayed-onset pseudophakic endophthalmitis were treated at KKESH. Of the 17 cases, only 5 cases developed delayed-onset endophthalmitis, among 29,509 cataract surgeries performed at KKESH, indicating an incidence rate of 0.017% (5/29,509). The mean time between cataract surgery and diagnosis of endophthalmitis was 5+/-2.48 months. The culture isolates revealed Propionibacterium acnes in 7 (41.2%) eyes, polymicrobial (mixed) infections in 3 (17.6%) eyes, Staphylococcus species in 3 (17.6 %) eyes, fungal infections in 3 (17.6%) eyes, and Alcaligenes xylosoxidans in 1 (5.9%) eye. The mean follow-up period was 29.8 months. The final visual outcomes were as follows: 7 eyes (41.2%) achieved a final best-corrected visual acuity of >or=20/60; 6 eyes (35.3%) achieved a best-corrected visual acuity of <20/60 to >or= count fingers; 2 eyes (11.8%) had hand motion to light perception vision; and 2 eyes (11.8%) were enucleated.

CONCLUSIONS

In this study, infection by P acnes was the most common cause of delayed-onset pseudophakic endophthalmitis and had the most favorable visual outcome, whereas fungal endophthalmitis had the worst visual prognosis.

Fundus albipunctatus and retinitis punctata albescens in a pedigree with an R150Q mutation in RLBP1

Fundus albipunctatus (FA; OMIM 136880) is a rare form of apparently stationary night blindness characterized by the presence of myriad symmetrical round white dots in the fundus with a greater concentration in the midperiphery. A distantly similar but distinct clinical entity, retinitis punctata albescens (RPA), is also characterized by aggregation of irregular white flecks but is progressive and evolves to generalized atrophy of the retina. We studied 4 consanguineous kindreds diagnosed with FA from Saudi Arabia. Given the substantial phenotypic variation and overlap between different flecked retinal dystrophies, we evaluated all known genes associated with such conditions by both genetic analysis and direct sequencing. In one kindred, KKESH-099, we identified a homozygous R150Q alteration in RLBP1, the gene encoding the cellular retinaldehyde binding protein, associated previously with both recessive retinitis pigmentosa (arRP) and RPA. Examination of several patients aged 3-20 years over a 9-year period presented no evidence for either RP or RPA. In contrast, clinical examination of individuals with the same mutation in their fourth and fifth decade revealed signs consistent with RPA. The data suggest that the R150Q mutation in RLBP1 may result in RPA with slow progression. More importantly, younger individuals diagnosed with the milder disorder FA thought to be stationary may evolve to a more devastating and progressive phenotype.

Whole-exome sequencing identifies ALMS1, IQCB1, CNGA3, and MYO7A mutations in patients with Leber congenital amaurosis

It has been well documented that mutations in the same retinal disease gene can result in different clinical phenotypes due to difference in the mutant allele and/or genetic background. To evaluate this, a set of consanguineous patient families with Leber congenital amaurosis (LCA) that do not carry mutations in known LCA disease genes was characterized through homozygosity mapping followed by targeted exon/whole-exome sequencing to identify genetic variations. Among these families, a total of five putative disease-causing mutations, including four novel alleles, were found for six families. These five mutations are located in four genes, ALMS1, IQCB1, CNGA3, and MYO7A. Therefore, in our LCA collection from Saudi Arabia, three of the 37 unassigned families carry mutations in retinal disease genes ALMS1, CNGA3, and MYO7A, which have not been previously associated with LCA, and 3 of the 37 carry novel mutations in IQCB1, which has been recently associated with LCA. Together with other reports, our results emphasize that the molecular heterogeneity underlying LCA, and likely other retinal diseases, may be highly complex. Thus, to obtain accurate diagnosis and gain a complete picture of the disease, it is essential to sequence a larger set of retinal disease genes and combine the clinical phenotype with molecular diagnosis.

Acute-onset nosocomial endophthalmitis after cataract surgery: incidence, clinical features, causative organisms, and visual outcomes

PURPOSE

To estimate the incidence of acute-onset endophthalmitis after cataract surgery and to report its clinical features, microbiology, and final visual outcomes.

SETTING

King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.

METHODS

This was a retrospective observational case series.

RESULTS

The 10-year incidence of acute-onset endophthalmitis after cataract surgery was 0.068%: 0.049% for extracapsular cataract extraction (ECCE) and 0.085% for clear corneal phacoemulsification (P = .268). The incidence of endophthalmitis was 0.053% during the first 5 years of the study and 0.08% during the next 5 years. The most common presenting features were pain and poor red reflex. Of the 20 cases, 18 were culture positive. The culture isolates showed Staphylococcus species in 7 eyes (35%), Streptococcus species in 7 eyes (35%), polymicrobial or mixed infections in 3 eyes (15%), and Propionibacterium acnes in 1 eye (5%). Two patients (10%) achieved a final visual acuity of 20/40 or better, 5 (25%) had worse than 20/40 to better than 20/200, and 8 (40%) had worse than 20/200; 5 eyes (25%) were eviscerated. Visual outcomes were good in endophthalmitis cases after phacoemulsification and in cases caused by Staphylococcus epidermidis and worse in cases that had Streptococcus species endophthalmitis.

CONCLUSIONS

Clear corneal phacoemulsification had a 1.73-fold higher risk for acute endophthalmitis than ECCE. Although the incidence of endophthalmitis after ECCE was lower than after phacoemulsification, the outcome was much worse in post-ECCE endophthalmitis cases. Poor visual outcomes were associated with more virulent organisms and delayed presentation.

Association of Aniridia and Dry Eyes

PURPOSE

To study the association between congenital aniridia and dry eyes, and the status of limbal stem cells.

DESIGN

Single-center, retrospective, noninterventional, comparative case series.

PARTICIPANTS

Twenty patients (36 eyes) diagnosed with congenital aniridia.

METHODS

Retrospective review of medical records at the King Khaled Eye Specialist Hospital in Riyadh, Saudi Arabia to identify all cases of congenital aniridia. Selected patients were requested to undergo further testing, especially for evaluation of dry eyes. Full ocular examinations were performed, including examination of the meibomian gland orifices and dry eye evaluation (by predetermined criteria of tear breakup time, tear meniscus level, presence of mucoid secretions, Schirmer's test with and without anesthesia, and fluorescein and rose Bengal staining patterns of the cornea and conjunctiva). Cytological evaluation was performed in 23 aniridic eyes by impression cytology to determine limbal stem cell status relative to control normal eyes.

MAIN OUTCOME MEASURES

Abnormal tear film production and stability, meibomian gland dysfunction, severity of corneal involvement, and limbal stem cell deficiency.

RESULTS

Twenty patients (36 eyes) diagnosed with congenital aniridia were classified into 3 groups according to the severity of corneal involvement: mild (2 eyes), moderate (21 eyes), and advanced (13 eyes) corneal changes. Tear breakup time was reduced by an average of 5 seconds in 90.7% of cases, tear meniscus levels were reduced to <0.5 mm in 88.6% of cases, and stenosed meibomian orifices were found in 77.8% of patients. Dry eyes (94%) correlated with the severity of corneal involvement (P = 0.001). Impression cytology revealed metaplasia in all tested cases. Furthermore, 8 of 23 eyes (35%) and 15 of 23 eyes (65%) had early and advanced limbal stem cell deficiency, respectively.

CONCLUSIONS

Abnormal tear film stability and meibomian gland dysfunction are newly identified factors in patients with aniridia. Both correlate to the severity of ocular surface disease. Impression cytology is informative in diagnosing various degrees of limbal stem cell deficiency, which is present in all tested aniridia eyes.

Bacterial keratitis after primary pediatric penetrating keratoplasty

PURPOSE

To determine the prevalence, microbiological profile, and prognosis for bacterial keratitis after primary pediatric penetrating keratoplasty (PKP).

DESIGN

Retrospective case series.

METHODS

Retrospective review of all cases of primary PKP performed in children 12 years of age or younger at the King Khaled Eye Specialist Hospital between January 1, 1990 and December 31, 2005 and inclusion of all postoperative cases of culture-positive, bacterial keratitis.

RESULTS

Culture-positive bacterial keratitis developed in 35 (17.3%) of 202 primary keratoplasties. Gram-positive organisms were cultured in 91.4% of infected eyes and accounted for 77.6% of isolates. Streptococcus pneumoniae was the most common organism. No eyes achieved a final visual acuity of 20/40 or better, while 65.7% had hand motions or worse.

CONCLUSIONS

Bacterial keratitis after pediatric keratoplasty is a serious complication that is associated with a high risk of graft failure and poor visual outcome.

Analysis and comparison of proteomic profiles of tear fluid from human, cow, sheep, and camel eyes

PURPOSE

To investigate the tear proteome profiles of human, cow, sheep, and camel comparatively and to explore the difference of tear protein profiles among different species.

METHODS

Tears were collected from both eyes of 25 clinically healthy volunteers, 50 cows, 25 sheep, and 50 camels. Pooled tear protein samples were separated by SDS-PAGE and two-dimensional electrophoresis. Protein spots of differential expression were excised and subjected to in-gel digestion and identification by matrix assisted laser desorption/ionization-time-of-flight/time-of-flight mass spectrum analysis. Because of the incomplete genomic data of cow, sheep, and camel, a combined strategy of de novo sequencing and BLAST (Best Local Alignment Search Tool) homology searching was also used for protein identification. The differentially expressed proteins were validated by Western blot analysis.

RESULTS

On comparison with human tears (182 ± 6 spots), 223 ± 8, 217 ± 11, and 241 ± 3 well-resolved protein spots were detected in triphenylmethane dye-stained gels of cow, sheep, and camel tears, respectively. Similar high-abundant proteins (lactoferrin, lysozyme, etc.) were found in all tear fluids. Tear lipocalins have been identified in cow and sheep tears. BLAST searching revealed a 21-kDa protein, identical with human vitelline membrane outer layer protein 1 (VMO1) homolog, in camel tears. The Western blot confirmed that VMO1 homolog was present in both camel and sheep tears but not in human and cow tears.

CONCLUSIONS

The comparative proteomic analyses of tears from healthy humans, cows, sheep, and camels were first reported. Differential protein expression existed in the tear among species, offering useful information for further study on tear proteins and the related ocular diseases.

Calotropis procera (ushaar) keratitis

PURPOSE

To report a case of permanent endothelial cell injury after intracorneal penetration of milky latex from Calotropis procera (ushaar).

DESIGN

Interventional case report.

METHODS

A 40-year-old patient developed painless corneal edema despite minimal epithelial injury after exposure to ushaar latex.

RESULTS

Confocal and specular microscopy confirmed permanent endothelial cell loss with morphologic alteration after intracorneal penetration of ushaar latex. Corneal edema resolved completely after 2 weeks, although reduced endothelial cell count and abnormal morphology persisted.

CONCLUSION

Ushaar latex is capable of penetrating the corneal stroma and inducing permanent loss of endothelial cells. Corneal edema resolves if sufficient endothelial cell viability is still present after resolution of ushaar keratitis.

Kinetic analysis of the toxicological effect of tacrine (Cognex) on human retinal acetylcholinesterase activity

For the first time, kinetic parameters of the effect of tacrine, an anti-cholinesterase inhibitor of therapeutic potential in Alzheimer's disease has been studied on human retinal acetyl-cholinesterase (AChE). Tacrine inhibited the AChE activity in a concentration dependent manner, the IC(50) being about 45 nM. The Michaelis-Menten constant (K(m)) for the hydrolysis of acetylthiocholine iodide was found to be 0.120 mM and this value was increased by 4-52.8% in the presence of tacrine. V(max) was observed to be 2.23 micromol/h per mg protein for the control system, while it was decreased by 14.73-56.25% in the tacrine treated systems. Dixon as well as Lineweaver-Burk plots and their secondary replots indicated that the nature of the inhibition was of the mixed type, i. e. a combination of competitive and noncompetitive inhibition. The values of K(i) and K(I) were estimated to be as 37.76 and 64.36 nM, respectively.

Penetrating keratoplasty for macular corneal dystrophy

PURPOSE

To determine the prognosis of penetrating keratoplasty (PK) for macular corneal dystrophy (MCD).

DESIGN

Single-center, retrospective, interventional, noncomparative case series.

PARTICIPANTS

One hundred forty-one patients (229 eyes) with MCD.

INTERVENTION

Retrospective review of the medical record of every patient who underwent primary PK for histopathologically confirmed MCD at the King Khaled Eye Specialist Hospital between January 1, 1983 and December 31, 2002 and for whom at least 12 months of follow-up is available.

MAIN OUTCOME MEASURES

Visual acuity (VA), graft survival, and postoperative complications.

RESULTS

After a mean follow-up period of 5.9+/-3.8 years (range, 1-17), the mean best-corrected VA was 20/50. At the most recent visit, 206 (90.0%) grafts were clear, and 23 (10.0%) had failed. Probabilities of graft survival were 98.1% at 1 year, 89.8% at 5 years, 82.1% at 10 years, and 74.1% at 15 years. There was a statistically significant increased likelihood of graft failure if the patient was older than 40 years at the time of surgery (P<0.00003). The differences in graft failure between patients older than 40 and those younger were not attributable to statistically significant differences in duration of follow-up, donor age, or donor endothelial cell counts. Corneal endothelial rejection episodes occurred in 47 (20.0%) grafts, but resulted in irreversible graft failure in only 8 (3.5%) eyes. Eighteen (27.3%) of 66 eyes with a recipient size of > or =7.5 mm developed a graft rejection episode, compared with 27 (16.6%) of 163 eyes with a recipient size of <7.5 mm (P = 0.04). Microbial keratitis occurred in 14 (6.1%) grafts and was more likely to occur in patients over 40 (14.0% vs. 3.0%, P = 0.01). Clinically significant recurrence was observed in 12 (5.2%) grafts, after a mean interval of 84+/-48.2 months, and was directly related to patient age (P = 0.04) and inversely related to donor graft size (P = 0.04).

CONCLUSIONS

Good visual results and excellent graft survival can be achieved after PK for MCD. The risk of graft failure is higher in patients older than 40 years.

L-Carnitine Protects Human Retinal Pigment Epithelial Cells from Oxidative Damage

PURPOSE

To determine the efficacy of L-carnitine (LC) against oxidative changes in human retinal pigment epithelium (RPE) cells.

METHODS

The RPE cells from human donor eyes were cultured in Hams F-10 medium. The effect of LC on H2O2-induced morphologic changes in the RPE cells was analyzed by light microscopy. Reduction in cell death after the impact of LC treatment on H2O2-treated cells was analyzed by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assays. In addition, the effect of H2O2 on the activity of RPE-antioxidant enzymes, glutathione (GSH) and superoxide dismutase (SOD), and LC-induced protection was also determined.

RESULTS

LC protected the RPE cells by inhibiting the peroxide-induced cytopathic effect from 50% to 10%. Nuclear condensation observed in 40% of the H2O2-treated cells decreased to 20% after LC treatment. The MTT assays demonstrated that 100 microM oxidant caused appreciable cell death, which was reduced by LC treatment; however, 100% protection was not achieved. Significant peroxide-induced cell death was seen within 5 hr of H2O2 treatment, and a quantifiable reduction was observed after LC treatment for a similar time period. The change in the antioxidant potential of the RPE induced by oxidative stress was restored by LC treatment, as demonstrated by an increase in GSH and SOD activities.

CONCLUSIONS

LC is capable of protecting the RPE cells from H2O2-induced oxidative damage, implying that micronutrients can have a positive effect and can play an important role in the treatment of oxidation-induced ocular disorders. Further studies are needed to understand the mechanism of LC-induced protection to the RPE cells.

Ocular mycosis at a referral center in Saudi Arabia: A 20-year study

PURPOSE

To review the clinical experience of fungal keratitis cases at King Khaled Eye Specialist Hospital (KKESH) in Riyadh, Saudi Arabia.

METHODS

Retrospective observational review and analysis of 124 patient charts with confirmed diagnosis of fungal keratitis between 1984 and 2004.

RESULTS

One hundred and twenty four eyes of 124 patients had proven fungal infection; 101 eyes had fungal keratitis and 23 eyes had fungal endophthalmitis complicating keratitis. Estimated proportion of fungal keratitis and endophthalmitis was 10.3%. Mean age was 55 years with male predominance (79.0%). Commonly associated factors were previous intraocular surgery (38.7%) and trauma (20.9%). Major risk factor for progressing to endophthalmitis was previous intraocular surgery (65.2%), p < 0.001. Initial laboratory results were fungal positive only in 30.6% (p < 0.001). Commonest organisms isolated were Aspergillus spp. (29.8%) followed by Trichophyton sp. (16.1%), then Candida and Fusarium sp. Comparison of both phases of the study showed improvement in the rate of successfully treated cases from 34.6% to 58.3%, and a decline in cases progressing to endophthalmitis from 25.0% to 13.9%. Therapeutic penetrating keratoplasty increased from 26.9% to 73.6% (p < 0.001). Thirteen eyes required enucleation or evisceration.

CONCLUSIONS

In contrast to other studies on fungal keratitis, Aspergillusspp. and Trichophyton sp. were the most commonly isolated fungal pathogens; the former carries the worst prognosis. Risk factors included previous intraocular surgery and trauma. Poor outcome was associated with Aspergillus spp., delayed presentation, previous intraocular surgery and late surgical intervention. This study recommends early surgical intervention to improve the outcome.

Heparin surface-modified intraocular lenses in patients with inactive uveitis or diabetes

OBJECTIVE

This study aimed to determine whether heparin surface-modified (HSM) intraocular lenses (IOLs) with a hydrophilic surface would reduce cell adherence and other postoperative changes compared with the conventional polymethylmethacrylate (PMMA) IOLs in patients with either diabetes mellitus or inactive uveitis.

DESIGN

The study design was a randomized, double-masked, clinical trial.

PARTICIPANTS

Twenty-five patients with bilateral cataracts, 14 with inactive anterior uveitis and 11 with diabetes, with an age range of 11 to 81 years (mean, 52.8 years) participated.

INTERVENTION

Bilateral cataract extraction with posterior chamber IOL implantation was measured, each patient receiving an HSM lens in one eye and a PMMA lens in the other. Pharmacia one-piece HSM and PMMA IOLs were used. Postoperative ocular changes were evaluated at regular intervals for 24 months in patients with inactive uveitis and for 6 months in patients with diabetes. Patients and physicians alike were unaware of which eye contained which lens until postoperative results were compiled. Records were kept by a study coordinator.

MAIN OUTCOME MEASURES

Comparisons of posterior synechiae, IOL cellular deposits, and posterior capsular fibrosis between PMMA and HSM IOLs were measured.

RESULTS

Using the chi-square test, no statistically significant difference was found between the HSM and PMMA IOLs in the number of cellular deposits found on the anterior IOL surface, the number of adhesions between the iris and IOL, or the incidence of capsular opacification.

CONCLUSION

The HSM and PMMA IOLs showed similar postoperative results in patients with inactive uveitis or diabetes mellitus.

Pigmented hypopyon in association with Listeria monocytogenes endopthalmitis: an interesting case report following refractive surgery procedure with literature review

Purpose:

Listeria monocytogenes is an aerobic, motile, gram positive bacillus recognized as an intercellular pathogen in human where it most frequently affects neonates, pregnant women, elderly patients, and immunosuppressed individuals as well as healthy persons. Ocular listeriosis is rare, most frequently in the form of conjunctivitis, but has been also shown to cause rarely endophthalmitis with pigmented hypopyon and elevated intraocular pressure such as in our case.

Materials and Methods:

We are reporting one immunocompetent patient presenting with dark hypopyon following laser refractive procedure. His clinical findings, investigations, and further management are all described with relevant literature review of similar cases.

Results:

Diagnosis of ocular listeriosis was confirmed by positive culture of anterior chamber (AC) aspirate with identification of the above organism. His visual outcome was satisfactory with good preserved vision.

Conclusion:

We believe that his ocular infection was exogenous and that ophthalmologists should be aware of the causative organisms of colored hypopyon to avoid delayed diagnosis.

Exclusion of AR-CHED from the chromosome 20 region containing the PPMD and AD-CHED loci

Congenital hereditary endothelial dystrophy (CHED) is a disorder of the corneal endothelium and has been recognized to segregate in families with both autosomal dominant (AD) and autosomal recessive (AR) modes of transmission. AD-CHED has been previously linked to the pericentric region of chromosome 20. Posterior polymorphous dystrophy (PPMD), a corneal endothelial disorder showing phenotypic overlap with CHED, has also been previously genetically mapped to this region. The genetic interval containing AD-CHED is within the larger genetic interval containing the PPMD locus. This study sought to determine whether AR-CHED segregating in a consanguineous Saudi Arabian pedigree is linked to the previously mapped and overlapping loci for AD-CHED and PPMD on the pericentric region of chromosome 20. Forty members of a consanguineous Saudi Arabian pedigree segregating AR-CHED were ascertained. Short tandem-repeat polymorphic markers from the 20 cM interval on chromosome 20 containing both the PPMD and AD-CHED loci were used to genotype these individuals. LOD score analysis of the genotype data with the MENDEL software package utilizing a model of autosomal recessive inheritance with complete penetrance showed exclusion of CHED from the entire PPMD/AD-CHED interval by utilizing overlapping intervals of LOD scores of at least -2. The results obtained demonstrate that AR-CHED is not allelic to either AD-CHED or PPMD, although it has been proposed that AD-CHED may be allelic to PPMD. Thus, there are at least two genes responsible for CHED and PPMD.

Prevalence and histopathological characteristics of corneal stromal dystrophies in Saudi Arabia

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.

Decentration and Cataract Formation 10 Years Following Posterior Chamber Silicone Phakic Intraocular Lens Implantation

PURPOSE

To report a 10-year follow-up for bilateral implantation of a Chiron Adatomed silicone posterior chamber phakic intraocular lens (PIOL).

METHODS

A 32-year-old man presented with bilateral blurred vision and monocular diplopia in the left eye of 2 years' duration.

RESULTS

Slit-lamp microscopy showed bilateral anterior subcapsular cataract and temporal PIOL decentration, and no visible space between the PIOL and crystalline lens in the right eye. After explantation of the posterior chamber PIOL, lens aspiration, and IOL implantation, uncorrected visual acuity improved to 20/15 in the right eye. Scanning electron microscopy examination showed denser deposits on the central portion of the back surface when compared with the edges.

CONCLUSIONS

Long-term follow up of certain designs of posterior chamber PIOLs may reveal late occurrence of complications. Cataract formation may be related to direct contact between the implanted and crystalline lenses.

Corneal xanthogranuloma in association with multiple endocrine neoplasia 1: A clinicopathologic case report and review of the literature

Juvenile xanthogranuloma (JXG) is a benign inflammatory condition of uncertain pathogenesis. It is characterized by skin and ocular involvement – typically in the iris – in children. It has been reported in older age groups and has been also observed to involve other ocular structures such as the cornea and conjunctiva.

In this case report, we are presenting an extensive right eye corneal lesion in a 43-year old male which showed the typical histopathological feature of JXG and in association with multiple endocrine neoplasia (type 1). Similar cases in the English-language literature have been also reviewed.

Candida parapsilosis corneal graft infection from a single eye center: Histopathologic report of 2 cases

Fungal keratitis accounts for 6–53% of all cases of ulcerative keratitis in variable studies. The majority of cases are due to septate fungi. The abnormal cornea in cases of dry eye syndrome, chronic ulceration, erythema multiform and possibly HIV infection is infected more commonly with Candida, most commonly Candida albicans. Candida parapsilosis affects neonates and intensive care unit (ICU) patients and it has been recently found with increasing frequency. In a previous study on mycotic keratitis in our tertiary eye hospital, filamentous fungi were more commonly isolated than yeasts. We are presenting 2 successive cases of corneal graft infection by Candida parapsilosis referred to us from another eye center to attract the attention of ophthalmologists and health workers to such an infection.