Cornea plana 2
| Cornea plana 2 | |
|---|---|
| Other names | Autosomal recessive Cornea plana, CNA2. |
 | |
| Cornea plana 2 is inherited in an autosomal recessive manner. | |
| Specialty | Medical genetics  |
Cornea plana 2 (CNA2) is a congenital disorder that causes the cornea to flatten and the angle between the sclera and cornea to shrink.[1] This could result in the early development of arcus lipoides, hazy corneal limbus, and hyperopia.[2] There is evidence that cornea plana 2 is caused by mutations in KERA gene encoding keratocan.[3] Cornea plana 2 is an autosomal recessive disorder.[4]
Signs and symptoms
Cornea plana commonly presents as a flat cornea, early-onset arcus lipoides, low anterior chamber depth, and an indistinct border between the sclera and cornea due to a decreased angle between the two.[2] Although a small corneal diameter is anticipated, measuring it can be challenging because the scleral tissue overlaps the cornea by a few millimeters. In the patients who have cornea plana, the anterior chamber depth has been found to vary from 0.8 to 2.1 mm.[5]
Moreover, high hyperopia, strabismus, microcornea, posterior embryotoxon, iridocorneal adhesions, iris lumps, iris wasting, and pupillary abnormalities can all be present.[6] Instead of hyperopia, myopia has been identified in a few cases.[7] As many as 90 percent of cases have a bilateral presentation, which is linked to sclerocornea.[1] Finally, congenital ptosis has also been reported, and the absence of corneal protrusion is most likely the cause.[5]
Diagnosis
Clinical presentation, keratometry,[7] pachymetry, and endothelial imaging are used to make the diagnosis.[8]
Since the decreased refraction in the autosomal recessive form is more severe than in the autosomal dominant form, corneal refraction measurements can be used to differentiate between CNA1 and CNA2.[5]
Histology is distinguished by acanthosis, keratinization of the corneal epithelium, Bowman's membrane defects, and stromal vascularization and scar formation.[4]
See also
References
- ^ a b Sutton, Gerard; Lawless, Michael A; Rogers, Christopher M (1995). "Cornea plana". Australian and New Zealand Journal of Ophthalmology. 23 (1). Wiley: 74–75. doi:10.1111/j.1442-9071.1995.tb01651.x. ISSN 0814-9763. PMID 7619462.
- ^ a b Tahvanainen, E; Forsius, H; Kolehmainen, J; Damsten, M; Fellman, J; de la Chapelle, A (February 1, 1996). "The genetics of cornea plana congenita". Journal of Medical Genetics. 33 (2). BMJ: 116–119. doi:10.1136/jmg.33.2.116. ISSN 1468-6244. PMC 1051836. PMID 8929947.
- ^ Pellegata NS, Dieguez-Lucena JL, Joensuu T, Lau S, Montgomery KT, Krahe R, Kivelä T, Kucherlapati R, Forsius H, de la Chapelle A (May 2000). "Mutations in KERA, encoding keratocan, cause cornea plana". Nat. Genet. 25 (1): 91–5. doi:10.1038/75664. PMID 10802664. S2CID 8837115.
- ^ a b Sigler-Villanueva, Aldo; Tahvanainen, Esa; Lindh, Sinikka; Dieguez-Lucena, Jose; Forsius, Henrik (1997). "Autosomal dominant cornea plana: Clinical findings in a Cuban family and a review of the literature". Ophthalmic Genetics. 18 (2). Informa UK Limited: 55–61. doi:10.3109/13816819709057116. ISSN 1381-6810. PMID 9228241.
- ^ a b c Forsius, Henrik; Damsten, Margareta; Eriksson, Aldur W.; Fellman, Johan; Lindh, Sinikka; Tahvanainen, Esa (1998). "Autosomal recessive cornea plana. A clinical and genetic study of 78 cases in Finland". Acta Ophthalmologica Scandinavica. 76 (2). Wiley: 196–203. doi:10.1034/j.1600-0420.1998.760215.x. ISSN 1395-3907. PMID 9591953.
- ^ Aldave, Anthony J.; Sonmez, Baris; Bourla, Nirit; Schultz, Gerald; Papp, Jeanette C.; Salem, Andrew K.; Rayner, Sylvia A.; Yellore, Vivek S. (2007). "Autosomal Dominant Cornea Plana is not Associated with Pathogenic Mutations inDCN, DSPG3, FOXC1, KERA, LUM,orPITX2". Ophthalmic Genetics. 28 (2). Informa UK Limited: 57–67. doi:10.1080/13816810701351321. ISSN 1381-6810. PMID 17558846. S2CID 23491990.
- ^ a b Fogla, Rajesh; Indumathy, Thazethaeveetil R. (2020). "Customized toric intraocular lens implantation in cornea plana". Journal of Cataract and Refractive Surgery. 46 (12). Ovid Technologies (Wolters Kluwer Health): e11–e14. doi:10.1097/j.jcrs.0000000000000350. ISSN 0886-3350. PMID 32818351. S2CID 221221090.
- ^ Ramappa, Muralidhar; Achanta, Divya Sree Ramya; Mohamed, Ashik; Chaurasia, Sunita (August 18, 2020). "Corneal endothelial alterations in Recessive Cornea Plana: a report of 4 patients and review of literature". Ophthalmic Genetics. 41 (6). Informa UK Limited: 659–662. doi:10.1080/13816810.2020.1804944. ISSN 1381-6810. PMID 32811257. S2CID 221181241.
Further reading
- Khan, Arif O. (2012). "Cornea Plana". Genetic Diseases of the Eye. Oxford University Press. pp. 85–91. doi:10.1093/med/9780195326147.003.0006. ISBN 978-0-19-532614-7.
- Coleman, Michael (2018). "Cornea Plana". Encyclopedia of Ophthalmology. Berlin, Heidelberg: Springer Berlin Heidelberg. pp. 513–514. doi:10.1007/978-3-540-69000-9_779. ISBN 978-3-540-68292-9.