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Serum Keratan Sulfate Concentration as a Measure of the Catabolism of Cartilage Proteoglycans
Published in Thomas F. Kresina, Monoclonal Antibodies, Cytokines, and Arthritis, 2020
Eugene J.-M. A. Thonar, James M. Williams, Brian A. Maldonado, Mary Ellen Lenz, Thomas J. Schnitzer, Giles V. Campion, Klaus E. Kuettner, M. Barry, E. Sweet
The corneal stromal matrix contains two distinct populations of PGs containing either KS or dermatan (chondroitin) sulfate. These PGs play important functional roles: they are located in the interfibrillar spaces and are thought to interact with the collagen fibrils and with each other to maintain the highly ordered matrix structure that provides optical transparency. Macular corneal dystrophy (MCD) is an inherited blinding disease characterized, in part, by the accumulation of opaque deposits containing an abnormal KS PG in the corneal stroma (38). The core protein of this PG is thought to be normal and was shown to be synthesized in normal amounts (39). Although the keratan chains in this PG are normally elongated, they are totally unsulfated (39). The most likely explanation for the lack of sulfation of the keratan chains is a deficiency in a sulfotransferase specific for keratan, a contention supported by the finding that the CS chains are normally sulfated or oversulfated (39).
Direct-to-Consumer Genetic Testing
Published in Emmanuel A. Kornyo, A Guide to Bioethics, 2017
Seventh, quality public health campaigns and education are at the forefront of health care. Genome-wide studies coupled with quality genetic tests within population holds sway for the development of robust personalized public health campaigns and education in ameliorating the emergence of epidemics and diseases. Iceland is cited by scholars as having one of the earliest models of genetic-based public health education program. deCode has pioneered one of the most successful population-based genomic sequencing in the world. The company and its affiliates have collected and analyzed many biospecimens, and have several genetic tests and as I have noted above, sequenced the genes of most of the population in Iceland and have created an extensive database. Iceland is unique because of its homogenous gene pools due to the possibility of its population from a homologous ancestry and centuries of isolation from the rest of the world. In addition, the population has kept extensive ancestry records making it easier to track generations. Because of these factors, geneticists are able to decipher some specific variants in the genes of sequenced genomes of the population responsible for diseases or phenotypic manifestations. In fact, there have been consistent efforts in encouraging Icelanders to sequence their genomes. A DTC genetic tests (which appears popular in Iceland), is essential for designing public- or population-based campaigns and education for individuals to make personal decisions about their health and families. DTC genetic tests if popularized strategically across the world can serve as important tool to help in designing, disseminating, and educating the public about their health in terms of the genetic markers and risks. For example, researchers believe 0.08% of the female population in Iceland have the mutation for the BRCA 2 genes that causes breast cancer with the clinical probability of carriers developing cancer to be over 80%! Another example is macular corneal dystrophy—an inherited eye disease. Compared to other population samples, Iceland has one of the highest incidences of this eye disease.22 As some scholars in a recent study noted, “The fact that the common ancestors of the parents of persons with macular corneal dystrophy were not found until in the 18th century, together with the available information of the geographical whereabouts of the families for more than two centuries may permit us to assume that heterozygous carriers for corneal dystrophy were present in Iceland early in the 18th century.”23 In simple terms, the ophthalmological condition is present in certain populations who are carriers of the gene. Thus, a public health-based campaign may target the population noted to be carriers of these genes to take appropriate precaution for clinical interventions, genetic counseling, and/or other decisions to manage the inheritable eye condition.24
Phototherapeutic Keratectomy in Macular and Granular Dystrophy: Two-year Results
Published in Seminars in Ophthalmology, 2020
Burcu Kemer Atik, Yusuf Yildirim, Orcun Sonmez, Gulsah Gumus, Burcin Kepez Yildiz, Alper Agca
Corneal dystrophies are a group of diseases with bilateral, progressive, non-inflammatory, and genetic transmission.1–3 Granular and macular corneal dystrophies are in the group of stromal corneal dystrophies and are characterized by corneal opacification.1,2 Granular corneal dystrophy is characterized by amorphous hyaline deposits in the stromal layer of the cornea, and shows autosomal dominant inheritance.1,4 Macular corneal dystrophy shows autosomal recessive genetic transition, and abnormal proteoglycan synthesis is the main mechanism in its pathogenesis.1,2,4 In both granular and macular dystrophy, abnormal corneal deposits diminish corneal transparency and this leads to decreased visual acuity. Penetrating keratoplasty, deep anterior lamellar keratoplasty, or phototherapeutic keratectomy (PTK) may be preferred in the treatment of corneal opacifications.1–4
Macular Corneal Dystrophy: An Updated Review
Published in Current Eye Research, 2021
Shalini Singh, Sujata Das, Chitra Kannabiran, Saumya Jakati, Sunita Chaurasia
Endothelial cell loss and recurrence in MCD after DALK has been more compared to Lattice dystrophy who had undergone DALK.59,60 Kawashima et al.5 reported increased endothelial cell loss after DALK in macular corneal dystrophy in comparison to lattice corneal dystrophy. Recurrence of primary pathology is less compared to lattice and granular dystrophy after DALK.60 Primary graft failure has been reported after DALK.61 Descemet stripping endothelial keratoplasty is described for an atypical case of MCD, wherein glycosaminoglycans deposits were predominantly at the endothelial level.16
Bilateral phototherapeutic keratectomy for corneal macular dystrophy in an adolescent: case report and review of the literature
Published in Ophthalmic Genetics, 2020
Melissa Shields, Jamie E. Craig, Emmanuelle Souzeau, Aanchal Gupta
Macular corneal dystrophy (MCD) is a recessively inherited stromal dystrophy that is characterised by diffuse ill-defined stromal opacities that spread peripherally towards the limbus with intervening haze. The opacities may also extend anteriorly and disrupt the integrity of the epithelial surface. As the disease progresses, the haziness extends deeper into the stroma and lesions enlarge and coalesce. Symptoms include glare, recurrent erosions and progressive visual loss resulting in severe visual impairment by early adulthood, usually necessitating PK (13).