Epithelial Corneal Dystrophy Research Articles

IC3D Classification of Corneal Dystrophies-Edition 3.

The International Committee for the Classification of Corneal Dystrophies (IC3D) was created in 2005 to develop a new classification system integrating current information on phenotype, histopathology, and genetic analysis. This update is the third edition of the IC3D nomenclature. Peer-reviewed publications from 2014 to 2023 were evaluated. The new information was used to update the anatomic classification and each of the 22 standardized templates including the level of evidence for being a corneal dystrophy [from category 1 (most evidence) to category 4 (least evidence)]. Epithelial recurrent erosion dystrophies now include epithelial recurrent erosion dystrophy, category 1 ( COL17A1 mutations, chromosome 10). Signs and symptoms are similar to Franceschetti corneal dystrophy, dystrophia Smolandiensis, and dystrophia Helsinglandica, category 4. Lisch epithelial corneal dystrophy, previously reported as X-linked, has been discovered to be autosomal dominant ( MCOLN1 mutations, chromosome 19). Classic lattice corneal dystrophy (LCD) results from TGFBI R124C mutation. The LCD variant group has over 80 dystrophies with non-R124C TGFBI mutations, amyloid deposition, and often similar phenotypes to classic LCD. We propose a new nomenclature for specific LCD pathogenic variants by appending the mutation using 1-letter amino acid abbreviations to LCD. Pre-Descemet corneal dystrophies include category 1, autosomal dominant, punctiform and polychromatic pre-Descemet corneal dystrophy (PPPCD) ( PRDX3 mutations, chromosome 10). Typically asymptomatic, it can be distinguished phenotypically from pre-Descemet corneal dystrophy, category 4. We include a corneal dystrophy management table. The IC3D third edition provides a current summary of corneal dystrophy information. The article is available online at https://corneasociety.org/publications/ic3d .

Clustered Regularly Interspaced Short Palindromic Repeats- a new era in Genomic technology and its applications in Theranostics

Clustered Regularly Interspaced Short Palindromic Repeats is termed as CRISPR. Bacteria having "spacer" sequences of deoxyribonucleic acid between the repeats of genomic sequences that resemble genomic sequences in viruses were found to have repetitive DNA sequences known as CRISPR.The CRISPR technology in genetic engineering has revolutionalized the field of medicine in treating various genetically linked diseases that are difficult to treat such as Lebers Congenital amaurosis, in which there is bi-allelic deletion caused by mutation in mitochondrial DNA MT-ND4(NADH ubiquinone oxidoreductase chain4) 1178G are treated by intravitreous injection of AAV2-ND4 produced by CRISPR-Cas9 genomic editing technology.CRISPR-Cas9 genomic editing is used to remove the expression of receptor Enhancer Protein-6 (Reep6 p.Leu135Pro ) gene that causes retinitis pigmentosa. Open angle Glaucoma caused by mutations in myocilin (MYOR) gene was effectively removed out by CRISPR-Cas9 editing technology. Mutation in KRT-12 gene that caused Meesman epithelial corneal dystrophy ( MECD) was alleviated by Cas9/sgRNA injection into the stroma of cornea. CRISPR-Cas9 genomic sequencing used in the treatment of Haemophilia -B , an inherited disease caused by mutation of factor IX gene Y371D was successfully modified by CRISPR-

Lisch Epithelial Corneal Dystrophy Is Caused by Heterozygous Loss-of-Function Variants in MCOLN1

To report the genetic etiology of Lisch epithelial corneal dystrophy (LECD). Multicenter cohort study. A discovery cohort of 27 individuals with LECD from 17 families, including 7 affected members from the original LECD family, 6 patients from 2 new families and 14 simplex cases, was recruited. A cohort of 6 individuals carrying a pathogenic MCOLN1 (mucolipin 1) variant was reviewed for signs of LECD. Next-generation sequencing or targeted Sanger sequencing were used in all patients to identify pathogenic or likely pathogenic variants and penetrance of variants. Nine rare heterozygous MCOLN1 variants were identified in 23 of 27 affected individuals from 13 families. The truncating nature of 7 variants and functional testing of 1 missense variant indicated that they result in MCOLN1 haploinsufficiency. Importantly, in the homozygous and compound-heterozygous state, 4 of 9 LECD-associated variants cause the rare lysosomal storage disorder mucolipidosis IV (MLIV). Autosomal recessive MLIV is a systemic disease and comprises neurodegeneration as well as corneal opacity of infantile-onset with epithelial autofluorescent lysosomal inclusions. However, the 6 parents of 3 patients with MLIV confirmed to carry pathogenic MCOLN1 variants did not have the LECD phenotype, suggesting MCOLN1 haploinsufficiency may be associated with reduced penetrance and variable expressivity. MCOLN1 haploinsufficiency is the major cause of LECD. Based on the overlapping clinical features of corneal epithelial cells with autofluorescent inclusions reported in both LECD and MLIV, it is concluded that some carriers of MCOLN1 haploinsufficiency-causing variants present with LECD.

Clinical manifestation of corneal epithelial dystrophy after LASIK

Modern keratorefractive surgery provides high efficiency, safety, predictability, stability of clinical and functional results of correction of various types of ametropia. In the process of preoperative diagnostics, standard and special examination methods are performed to exclude corneal diseases and determine the optimal technology for laser vision correction in each specific case. However, detection of subclinical forms of dystrophies and degenerations of the cornea is not always possible in the course of standard preoperative diagnostics. In this connection, the aim of this work is to present a clinical case of the manifestation of corneal epithelial dystrophy after laser vision correction. The article describes a rare case of clinical manifestation of corneal epithelial dystrophy after excimer laser vision correction, which was compensated by anti-inflammatory and corneoprotective therapy. Diagnostic studies are also separately described, including keratotopographic examination, optical coherence tomography of the anterior segment of the eyes and in vivo confocal microscopy of the cornea, the role of these research methods in the early diagnosis of degenerative processes of the cornea is noted. In vivo laser confocal microscopy is classified as a minimally invasive diagnostic manipulation that allows real-time analysis of all layers of the cornea at a level close to histological. Recently, this method of diagnosing the anterior segment of the eye has found wide application in clinical practice. The management of patients with corneal dystrophies requires increased attention from an ophthalmologist; anti-inflammatory and keratoprotective therapy of the cornea, followed by long-term dynamic monitoring of the eye condition, is topical as a prescribed treatment.

Эффективность лечебных мягких контактных линз при эпителиально-эндотелиальной дистрофии роговицы

Purpouse is to evaluate the effectiveness of therapeutic contact lenses (TCL) in epithelial-endothelial corneal dystrophy (EEDR). Material and methods. We observed 60 patients (70 eyes) with EEDR. Hydrophilic TCL with complex preparations with antioxidant and regenerative effects were used while treating EEDR. All patients underwent visometry, pneumotonometry, biomicroscopy, autorefractometry, ophthalmoscopy. Results. With EEDR, patients complained of a sensation of a foreign body in the eyes and sharp pain in 91.4 % (64 eyes) of cases, redness in 100 % (70 eyes), photophobia in 100 % (70 eyes), tearing in 100 % (70 eyes) and decreased vision in 97.1 % (68 eyes) of cases. Therapeutic contact lenses (TCL) helped to relieve pain with 91.4 % (64 eyes) of patients. TCL contributed to corneal epithelialization in 94.3 % (66 eyes) of cases. TCL helped to maintain the inherent moisture of the cornea in 97.1 % (68 eyes) of cases by reducing the evaporation of moisture from the surface of the cornea. Conclusion. The use of a therapeutic contact lens in patients with EDRD made it possible to significantly relieve pain in 91.4 % of cases, but increased the healing time by means of corneal epithelialization in 94.3 % of patients. Keywords: epithelial and endothelial corneal dystrophy, bullous keratopathy, therapeutic contact lenses.

Clinical and morphological characteristics of corneal epithelial dystrophy (clinical observations)

This paper presents clinical observations that can be regarded as degeneration of the basement membrane of the corneal epithelium. Difficulties in identifying such forms of corneal dystrophies, on the one hand, are associated with limitation and polymorphism of the clinical picture, and, on the other hand, with insufficient information content of the basic diagnostic methods (i.e. the methods used during the initial examination). The presented clinical cases allow singling out the alarming and pathognomonic signs of the disease in the diagnostic algorithm. In the first case, attention should be paid to biomicroscopic changes in the superficial layers of the cornea and the optical defects, which can be regarded as a manifestation of an irregularity of corneal refraction. Identification of pathognomonic signs of the disease is possible on the basis of a detailed, close-to-morphological study of the structure of superficial corneal layers using confocal microscopy and optical coherence tomography. At the same time, the localization of the detected changes at the level of epithelial basement membrane and its basal sections is of crucial significance for substantiating the diagnosis. In addition, according to the literature data, recurrent erosions of the cornea of unclear etiology should be attributed to presumptive signs of degenerative changes in the basement membrane of the epithelium.

Detailed corneal and genetic characteristics of a pediatric patient with macular corneal dystrophy - case report

BackgroundCorneal dystrophies are a group of rare, inherited disorders that are usually bilateral, symmetric, slowly progressive, and not related to environmental or systemic factors. The majority of publications present the advanced form of the disease with a typical clinical demonstration. The initial signs and symptoms of different epithelial and stromal corneal dystrophies are not specific; therefore, it is very important to establish the early characteristic corneal features of these disorders that could guide the diagnostic process.Case presentationThe main purpose of this study was to report the differential diagnosis of a pediatric patient with bilateral anterior corneal involvement suspected of corneal dystrophy. An 8-year-old male patient presented with asymptomatic, persistent, superficial, bilateral, diffuse, anterior corneal opacities. Slit lamp examination results were not specific. Despite the lack of visible stromal involvement on the slit lamp examination, corneal analysis based on confocal microscopy and optical coherence tomography revealed characteristic features of macular corneal dystrophy (MCD). The diagnosis of MCD was confirmed by CHST6 gene sequencing. The early corneal characteristic features of MCD, established based on the findings of this case report, include corneal astigmatism (not specific), diffuse corneal thinning without a pattern of corneal ectasia (specific), and characteristic features on confocal microscopy (specific), including multiple, dark, oriented striae at different corneal depths.ConclusionsThe clinical examination should be complemented with corneal imaging techniques, such as confocal microscopy and optical coherence tomography. In patients suspected of corneal dystrophy, genetic testing plays an important role in establishing the final diagnosis.

Еfficacy of Combined Treatment of Epithelial and Endothelial Corneal Dystrophy Using Corneal Crosslinking and Automated Posterior Lamellar Keratoplasty

The purpose: to establish a combined approach to the treatment of patients with epithelial and endothelial cornea dystrophy (EED) based on a comparative study of the results of one-step and two-step methods. Patients and methods. The study included 75 patients (81 eyes) with corneal EED, who underwent surgical treatment at the Ufa Eye Research Institute from 2011 to 2016. The patients were divided into two groups — the main group consisted of 43 (46 eyes, 57 %) patients, who underwent the first stage of the CC before surgical treatment of EED, the second stage after 1–12 months — automated posterior lamellar keratoplasty (APLK). In the control group, isolated APLK was performed in 32 (35 eyes, 43 %) patients. Results. After CC (1–10 days) in the main group an increase in corneal thickness due to edema enhancement in the cornea stroma was observed in patients with stage I–III of the corneal EED. After 3 months, a decrease in corneal thickness was recorded in patients of the main group with I-II stages of the disease (p < 0.05), after 6 months — in all stages of the corneal EED compared with the control group (p < 0.05). According to optical coherence tomography (OCT), a decrease in the total cornea thickness in both зфешутеы groups was noted within 12 months after APLK: in the main group from 667 ± 65 μm initially to 594 ± 31 μm, in the control group, where there was a pronounced corneal edema from 787 ± 56 to 612 ± 67 μm. Conclusion. Corneal cross-linking in patients with I–III stages of corneal EED provides improvement of the cornea, manifested in reducing edema and its thickness. It allows to delay the implementation of the automated posterior lamellar keratoplasty without corneal deterioration in patients with stage I up to 6–12 months, in patients with stage II–III up to 3–6 months.

Epithelial Dystrophies of the Cornea

In 2015, the first revision of the international classification of corneal dystrophies (IC3D) has been published. According to this latest version of the IC3D the dystrophies of the cornea are divided into · epithelial and subepithelial dystrophies,. · epithelial-stromal TGFBI dystrophies,. · stromal dystrophies, and. · Descemet-membrane and endothelial dystrophies.. This article summarizes the epithelial and subepithelial dystrophies of the cornea, which, according to IC3D are the following: · epithelial basement membrane dystrophy (EBMD),. · epithelial recurrent erosion dystrophy (ERED),. · subepithelial mucinous corneal dystrophy (SMCD),. · Meesmann corneal dystrophy (MECD),. · Lisch epithelial corneal dystrophy (LECD),. · gelatinous drop-like corneal dystrophy (GDLD).. The main problem concerning almost all dystrophies of the corneal epithelium are epithelial defects (erosion) associated with pain, epiphora and red eyes. In addition, all dystrophies of the epithelium tend to relapse.While therapy is usually initiated with topical therapeutics, in the course of the disease invasive procedures like phototherapeutic keratectomy (PTK) (possibly with the administration of mitomycin C) or in severe cases even keratoplasty (preferably as deep anterior lamellar keratoplasty; DALK) have to be used. Due to the origin of the disease in the epithelial stem cells at the limbus, the replacement of these cells can also be discussed.

Combined Keratectomy and Localized Limbal Cauterization for Treating Lisch Epithelial Corneal Dystrophy

To present a new technique for treating Lisch epithelial corneal dystrophy (LECD) in cases of recurrence of the disease. We present a single case report of a 41-year-old man who presented to the cornea clinic with progressive loss of vision in the right eye. Slit-lamp examination showed a large white-gray whorl-like epithelial opacity connected to the limbus, which spread over the visual axis, affecting visual acuity. The left eye was uninvolved. After epithelial debridement was performed, histological analysis showed the nonkeratinized stratified flat epithelium, coalescent cytoplasmic vacuoles in some keratinocytes, and isolated cells with granular cytoplasm and small PAS negative nuclei, which confirmed the diagnosis of LECD. Despite partially successful treatment with several sequential epithelial debridements, the patient presented with confirmed recurrence of the disease soon after every treatment. Thus, focal epitheliectomy combined with localized cauterization of the limbal focus of origin was performed. Vision returned to normal, and there were no signs of recurrence at final follow-up 2 years later. Simple epitheliectomy combined with focal cauterization of the limbal focus of origin can be a simple, safe, and minimally invasive option for treatment of LECD.

Prevalence of subtypes of epithelial and sub-epithelial corneal dystrophy in Punjab-Pakistan

Prevalence of subtypes of epithelial and sub-epithelial corneal dystrophy in Punjab-Pakistan

Recurrent Corneal Erosions in Epithelial Corneal Dystrophies

The corneal epithelium is the most important structure of the ocular optical system. Recurrent corneal erosions can result from inflammation, trauma, degeneration and dystrophies. Epithelial basement membrane dystrophy (EBMD), epithelial recurrent erosion dystrophy (ERED) and Francheschetti and Meesmann's epithelial corneal dystrophy (MECD) can all - besides other signs and symptoms - result in more or less frequent corneal erosions. The pathomechanisms involved however are different. In EBMD, corneal erosions are facultative and clinical signs are often subtle. Aberrant basement membrane structures are associated with thinning of the epithelium and can be clinically identified as maps or fingerprints. In ERED, recurrent corneal erosions are - predominantly in the first decades of life - always present. A defect in the COL17A1 gene results in a dysfunctional hemidesmosome. In MECD, punctate corneal erosions are less frequent and result from intraepithelial microcysts which open spontaneously onto the ocular surface. Usually lubricants, therapeutic contact lenses and sometimes epithelial debridement and phototherapeutic keratectomy are the mainstay for treating corneal erosions in these three dystrophies.

Keratolimbal autograft transplantation as a possible new treatment of Lisch epithelial corneal dystrophy

Case reportThe case concerns 64-year-old woman with visual acuity of 20/40 in the right eye. Slit-lamp examination revealed a grey, feathery corneal opacification with intraepithelial microcysts compatible with Lisch epithelial corneal dystrophy (LECD). It was treated with epithelial debridements, contact lenses and mitomycin C, but the opacification recurred within months. The removal of limbus sector and autologous limbal transplantation (KLAT) were used successfully without recurrence. ConclusionsAfter removal of damaged limbus, KLAT should be considered as a treatment option for asymmetric LECD when other treatments have failed.

Trasplante autólogo de limbo como nuevo tratamiento de la distrofia corneal epitelial de Lisch

Case reportThe case concerns 64-year-old woman with visual acuity of 20/40 in the right eye. Slit-lamp examination revealed a grey, feathery corneal opacification with intraepithelial microcysts compatible with Lisch epithelial corneal dystrophy (LECD). It was treated with epithelial debridements, contact lenses and mitomycin C, but the opacification recurred within months. The removal of limbus sector and autologous limbal transplantation (KLAT) were used successfully without recurrence. ConclusionsAfter removal of damaged limbus, KLAT should be considered as a treatment option for asymmetric LECD when other treatments have failed.

Keratin 12 missense mutation induces the unfolded protein response and apoptosis in Meesmann epithelial corneal dystrophy.

Meesmann epithelial corneal dystrophy (MECD) is a rare autosomal dominant disorder caused by dominant-negative mutations within the KRT3 or KRT12 genes, which encode the cytoskeletal protein keratins K3 and K12, respectively. To investigate the pathomechanism of this disease, we generated and phenotypically characterized a novel knock-in humanized mouse model carrying the severe, MECD-associated, K12-Leu132Pro mutation. Although no overt changes in corneal opacity were detected by slit-lamp examination, the corneas of homozygous mutant mice exhibited histological and ultrastructural epithelial cell fragility phenotypes. An altered keratin expression profile was observed in the cornea of mutant mice, confirmed by western blot, RNA-seq and quantitative real-time polymerase chain reaction. Mass spectrometry (MS) and immunohistochemistry demonstrated a similarly altered keratin profile in corneal tissue from a K12-Leu132Pro MECD patient. The K12-Leu132Pro mutation results in cytoplasmic keratin aggregates. RNA-seq analysis revealed increased chaperone gene expression, and apoptotic unfolded protein response (UPR) markers, CHOP and Caspase 12, were also increased in the MECD mice. Corneal epithelial cell apoptosis was increased 17-fold in the mutant cornea, compared with the wild-type (P < 0.001). This elevation of UPR marker expression was also observed in the human MECD cornea. This is the first reporting of a mouse model for MECD that recapitulates the human disease and is a valuable resource in understanding the pathomechanism of the disease. Although the most severe phenotype is observed in the homozygous mice, this model will still provide a test-bed for therapies not only for corneal dystrophies but also for other keratinopathies caused by similar mutations.

Genotype and phenotype correlation of monogenic corneal dystrophies in population of central Poland

PurposeTo assess the genotype‐phenotype correspondence in monogenic corneal dystrophies caused by KRT,TGFBI and UBIAD1 genes mutation.Methods61 patients from 30 Polish families with clinically diagnosed epithelial and stromal corneal dystrophies participated in the study.Corneal phenotypes were assessed by slit lamp, AS‐OCT,and confocal microscopy in vivo. Genomic DNA was obtained from blood samples and respective exons (hot spots) were PCR amplified and sequenced on both strands.ResultsMolecular genetic testing revealed heterozygous missense p.E498V mutation (exon 7) of KRT3 in one family with Meesmann corneal dystrophy phenotype, p.R555W (exon 12) mutation in 19 patients diagnosed with granular type I dystrophy (GCD1). In two patients p.R124H mutation (GCD2, Avellino) was found. In three patients (2 families) heterozygous p.R124L (exon 4) mutation was identified and diagnosed as Reis‐Buecklers dystrophy. In two unrelated patient p.R555Q (exon 12) mutation typical for Thiel‐Behnke dystrophy was found. Heterozygous p.R124C (exon 4), p.T538R (exon 12) and p.H626R (exon 14) mutations were identified, respectively, in 10 patients diagnosed with lattice corneal dystrophy (LCD1). A novel p.L565P mutation was found in one family with late‐onset LCD.Among 18 idividuals (4 families) suffering from stromal Schnyder corneal dystrophy (SCD) molecular genetic testing revealed 3 different UBIAD1 gene mutations: p.N102S, p.D112N, p.T120R.ConclusionsThe genotype typical for monogenic corneal dystrophies caused by KRT and UBIAD1 genes mutation corresponds with its clinical phenotype. TGFBI is associated with phenotype heterogenity and in some cases only genetic tests may confirm the proper diagnosis.This indicates that a relatively straightforward molecular analysis can be a practical use in diagnosis of these conditions and associated genetic counseling.

CRISPR/Cas9 DNA cleavage at SNP-derived PAM enables both in vitro and in vivo KRT12 mutation-specific targeting.

CRISPR/Cas9-based therapeutics hold the possibility for permanent treatment of genetic disease. The potency and specificity of this system has been used to target dominantly inherited conditions caused by heterozygous missense mutations through inclusion of the mutated base in the short-guide RNA (sgRNA) sequence. This research evaluates a novel approach for targeting heterozygous single-nucleotide polymorphisms (SNPs) using CRISPR/Cas9. We determined that a mutation within KRT12, which causes Meesmann's epithelial corneal dystrophy (MECD), leads to the occurrence of a novel protospacer adjacent motif (PAM). We designed an sgRNA complementary to the sequence adjacent to this SNP-derived PAM and evaluated its potency and allele specificity both in vitro and in vivo. This sgRNA was found to be highly effective at reducing the expression of mutant KRT12 mRNA and protein in vitro. To assess its activity in vivo we injected a combined Cas9/sgRNA expression construct into the corneal stroma of a humanized MECD mouse model. Sequence analysis of corneal genomic DNA revealed non-homologous end-joining repair resulting in frame-shifting deletions within the mutant KRT12 allele. This study is the first to demonstrate in vivo gene editing of a heterozygous disease-causing SNP that results in a novel PAM, further highlighting the potential for CRISPR/Cas9-based therapeutics.

SiRNA Silencing of the Mutant Keratin 12 Allele in Corneal Limbal Epithelial Cells Grown From Patients With Meesmann's Epithelial Corneal Dystrophy

The aim of this study is to further assess our previously reported keratin 12 (K12)-Leu132Pro specific siRNA in silencing the mutant allele in Meesmann's Epithelial Corneal Dystrophy (MECD) in experimental systems more akin to the in vivo situation through simultaneous expression of both wild-type and mutant alleles. Using KRT12 exogenous expression constructs transfected into cells, mutant allele specific knockdown was quantified using pyrosequencing and infrared Western blot analysis, while the silencing mechanism was assessed by a modified rapid amplification of cDNA ends (5'RACE) method. Corneal limbal biopsies taken from patients suffering from MECD were used to establish cultures of MECD corneal limbal epithelial stem cells and the ability of the siRNA to silence the endogenous mutant KRT12 allele was assessed by a combination of pyrosequencing, qPCR, ELISA, and quantitative-fluorescent immunohistochemistry (Q-FIHC). The siRNA displayed a potent and specific knockdown of K12-Leu132Pro at both the mRNA and protein levels with exogenous expression constructs. Analysis by the 5'RACE method confirmed siRNA-mediated cleavage. In the MECD cells, an allele-specific knockdown of 63% of the endogenous mutant allele was observed without effect on wild-type allele expression. Combined with an effective delivery vehicle this siRNA approach represents a viable treatment option for prevention of the MECD pathology observed in K12-Leu132Pro heterozygous individuals.

Autosomal-dominant Meesmann epithelial corneal dystrophy without an exon mutation in the keratin-3 or keratin-12 gene in a Chinese family

Meesmann epithelial corneal dystrophy (MECD) is a dominantly inherited disorder, characterized by fragility of the anterior corneal epithelium and formation of intraepithelial microcysts. It has been described in a number of different ancestral groups. To date, all reported cases of MECD have been associated with either a single mutation in one exon of the keratin-3 gene (KRT3) or a single mutation in one of two exons of the keratin-12 gene (KRT12). Each mutation leads to a predicted amino acid change in the respective keratin-3 or keratin-12 proteins that combine to form the corneal-specific heterodimeric intermediate filament protein. This case report describes a four-generation Chinese kindred with typical autosomal-dominant MECD. Exon sequencing of KRT3 and KRT12 in six affected and eight unaffected individuals (including two spouses) did not detect any mutations or nucleotide sequence variants. This kindred demonstrates that single mis-sense mutations may be sufficient but are not required in all individuals with the MECD phenotype. It provides a unique opportunity to investigate further genomic and functional heterogeneity in MECD.

Allele-Specific siRNA Silencing for the Common Keratin 12 Founder Mutation in Meesmann Epithelial Corneal Dystrophy

To identify an allele-specific short interfering RNA (siRNA), against the common KRT12 mutation Arg135Thr in Meesmann epithelial corneal dystrophy (MECD) as a personalized approach to treatment. siRNAs against the K12 Arg135Thr mutation were evaluated using a dual luciferase reporter gene assay and the most potent and specific siRNAs were further screened by Western blot. Off-target effects on related keratins were assessed and immunological stimulation of TLR3 was evaluated by RT-PCR. A modified 5' rapid amplification of cDNA ends method was used to confirm siRNA-mediated mutant knockdown. Allele discrimination was confirmed by quantitative infrared immunoblotting. The lead siRNA, with an IC(50) of thirty picomolar, showed no keratin off-target effects or activation of TLR3 in the concentration ranges tested. We confirmed siRNA-mediated knockdown by the presence of K12 mRNA fragments cleaved at the predicted site. A dual tag infrared immunoblot showed knockdown to be allele-specific, with 70% to 80% silencing of the mutant protein. A potent allele-specific siRNA against the K12 Arg135Thr mutation was identified. In combination with efficient eyedrop formulation delivery, this would represent a personalized medicine approach, aimed at preventing the pathology associated with MECD and other ocular surface pathologies with dominant-negative or gain-of-function pathomechanisms.