Epithelial basement membrane dystrophy (EBMD) is a disorder of the eye that can cause pain and dryness. It is sometimes included in the group of corneal dystrophies. It diverges from the formal definition of corneal dystrophy since it is non-familial in most cases. It also has a fluctuating course, while for a typical corneal dystrophy the course is progressive. When it is considered part of this group, it is the most common type of corneal dystrophy. Signs and symptoms
Patients may complain of severe problems with dry eyes, or with visual obscurations. It can also be asymptomatic, and only discovered because of subtle lines and marks seen during an eye exam.EBMD is a bilateral anterior corneal dystrophy characterized by grayish epithelial fingerprint lines, geographic map-like lines, and dots (or microcysts) on slit-lamp examination. Findings are variable and can change with time. While the disorder is usually asymptomatic, up to 10% of patients may have recurrent corneal erosions, usually beginning after age 30; conversely, 50% of patients presenting with idiopathic recurrent erosions have evidence of this dystrophy. Pathophysiology
In some families autosomal dominant inheritance and point mutations in the TGFBI gene encoding keratoepithelin have been identified, but according to the International Committee for Classification of Corneal Diseases (IC3D) the available data still does not merit a confident inclusion of EBMD in the group of corneal dystrophies.
BBSome is proposed to be responsible for transporting intracellular vesicles to the base of the cilia and to play an important role in the ciliary function.Since abnormalities of cilia are known to be related to a wide range of disease symptoms including those commonly seen in BBS patients, it is now widely accepted that mutated BBS genes affect normal cilia function, which, in turn, causes BBS.A theory that photoreceptor cells are nourished by the IFT of retinal cilia now offers a potential explanation for the retinal dystrophy common in BBS patients after their early years of life.Genes involved include:

BBsome: BBS1, BBS2, ARL6/BBS3, BBS4, BBS5, BBS7, TTC8/BBS8, BBS10, TRIM32/BBS11 BBS12, CCDC28B, CEP290, TMEM67, MKS1, MKKS
chaperone: BBS6

Diagnosis
The diagnosis of BBS is established by clinical findings and family history. Molecular genetic testing can be used to confirm the diagnosis. Multigene panels offer the most effective approach in achieving molecular confirmation of BBS. Eponym
The syndrome is named after Georges Bardet and Arthur Biedl. The first known case was reported by Laurence and Moon in 1866 at the Ophthalmic Hospital in South London. Laurence–Moon–Biedl–Bardet syndrome is no longer considered as valid terms in that patients of Laurence and Moon had paraplegia but no polydactyly or obesity, which are the key elements of the Bardet–Biedl syndrome. Laurence–Moon syndrome is usually considered a separate entity. However, some recent research suggests that the two conditions may not be distinct.As of 2012, 14
(or 15) different BBS genes had been identified. References
External links

Overview at United States National Library of Medicine
Molecular diagnosis at NCBI