OMIM ID:
Exfoliation Glaucoma
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
Whitish flakes resembling dandruff appear on the anterior lens capsule during midlife, often accompanied by pigment. It is a progressive disorder in all aspects and once established does not regress. The condition is often asymmetrical and even unilateral, at least in some stages. This fibrillar material is deposited throughout the anterior chamber including the trabecular meshwork where it blocks the outflow mechanism leading to glaucoma. The latter is often severe and difficult to control. It is claimed that the risk of glaucoma is 6 times greater among such patients compared with individuals who do not have exfoliation. Cataract prevalence is higher among patients with exfoliation and those with cataracts have a higher prevalence of exfoliation. Dilation is often difficult in such patients and operative complications such as capsular rupture, lens mobility, and vitreous loss are greater. Posterior synechiae are more frequent in exfoliation patients. Pupillary block and angle closure glaucoma are additional glaucoma risks.
The majority of evidence suggests that the source of the exfoliation material is the extracellular matrix of ocular structures including the lens epithelium, iris pigment epithelium and the non-pigmented ciliary epithelium. The exact composition of the material, however, has not been established.
Systemic Features
Some consider this to be a systemic disease as well and have associated it with widespread cardiovascular complications, including hypertension, stroke, myocardial infarctions and transient ischemic attacks. Fibrillar material has been identified in autopsy material among many visceral organs including heart, kidney, liver, and CNS meninges. Physiologic or etiologic connections, however, have not been established. The mortality rate among patients with exfoliation syndrome does not appear to be increased and it is currently not recommended that all individuals with ocular pseudoexfoliation undergo general systemic evaluations.
Genetics
Inheritance
This disorder has an ethnic population distribution, an important indication of its genetic basis. It occurs with high frequency in Scandinavians, Amerindians, Greeks and selective black populations in Africa. It is not seen in Eskimos.
There is evidence that mutations in LOXL1 (15q22) confer susceptibility to exfoliation syndrome. However, a specific mutational basis and transmission pattern has yet to be determined. Available evidence is most suggestive of autosomal dominant inheritance but a multifactorial or susceptibility mechanism cannot be ruled out.
Pedigree
Autosomal dominant
Autosomal dominant disorders require only one mutation for the disease to be expressed. Since an affected parent has two chromosomes, only one of which has the mutant gene, parents can expect that half (50%) of their children will receive that one and inherit the disease. It is common for individuals that inherit the mutation, however, to not have evidence of the disease (nonpenetrance).
Autosomal dominant inheritance leads to a vertical pattern of transmission