Granular corneal dystrophy

Granular corneal dystrophy type I, Numerous irregular shaped discrete crumb-like corneal opacities

Granular corneal dystrophy type II, Variable sized crumb-like opacities in the corneal stroma that have become fused in areas giving rise to elongated and stellate shapes

Granular corneal dystrophy is a slowly progressive corneal dystrophy that most often begins in early childhood.

Granular corneal dystrophy has two types:

• Granular corneal dystrophy type I , also corneal dystrophy Groenouw type I, is a rare form of human corneal dystrophy. It was first described by German ophthalmologist Arthur Groenouw in 1890.^[1]

• Granular corneal dystrophy type II, also called Avellino corneal dystrophy or combined granular-lattice corneal dystrophy^[2] is also a rare form of corneal dystrophy. The disorder was first described by Folberg et al. in 1988. The name Avellino corneal dystrophy comes from the first four patients in the original study each tracing their family origin to the Italian province of Avellino.^[3]

Genetics

Granular corneal dystrophy is caused by a mutation in the TGFBI gene, located on chromosome 5q31.^[4] The disorder is inherited in an autosomal dominant manner.^[5] This indicates that the defective gene responsible for the disorder is located on an autosome (chromosome 5 is an autosome), and only one copy of the gene is sufficient to cause the disorder, when inherited from a parent who has the disorder.

The gene TGFBI encodes the protein keratoepithelin.^[5]

Clinical presentation

Granular corneal dystrophy is diagnosed during an eye examination by an ophthalmologist or optometrist. The lesions consist of central, fine, whitish granular lesions in the cornea. Visual acuity is slightly reduced.

Treatment

Corneal transplant is not needed except in very severe and late cases. Light sensitivity may be overcome by wearing tinted glassess.

See also

• Corneal dystrophy

References

1. Online 'Mendelian Inheritance in Man' (OMIM) 121900
2. Online 'Mendelian Inheritance in Man' (OMIM) 607541
3. Folberg R, Alfonso E, Croxatto JO, Driezen NG, Panjwani N, Laibson PR, Boruchoff SA, Baum J, Malbran ES, Fernandez-Meijide R (January 1988). "Clinically atypical granular corneal dystrophy with pathologic features of lattice-like amyloid deposits. A study of these families". Ophthalmology 95 (1): 46–51. doi:10.1016/s0161-6420(88)33226-4. PMID 3278259.
4. Munier, F. L.; Korvatska, E.; Djemaï, A.; Paslier, D. L.; Zografos, L.; Pescia, G.; Schorderet, D. F. (March 1997). "Kerato-epithelin mutations in four 5q31-linked corneal dystrophies". Nature Genetics 15 (3): 247–251. doi:10.1038/ng0397-247. PMID 9054935.
5. Paliwal, P.; Gupta, J.; Tandon, R.; Sharma, A.; Vajpayee, R. B. (Oct 2009). "Clinical and Genetic Profile of Avellino Corneal Dystrophy in 2 Families from North India". Archives of Ophthalmology 127 (10): 1373–1376. doi:10.1001/archophthalmol.2009.262. PMID 19822856.