OMIM ID:
Corneal Dystrophy, Fleck
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
This stromal dystrophy may be congenital as it can be seen in the first years of life. It is nonprogressive and generally has little clinical significance as it does not impair vision or require treatment in most cases. It is usually diagnosed on routine examination from the presence of multiple, minute, whitish or grayish discrete opacities throughout the stroma. The largest numbers are located centrally and posteriorly. These may be flat, round or oval, and sometimes resemble snowflakes. Keratocyte cell bodies contain cytoplasmic inclusions or vacuoles likely as the result of defective intracellular organelle trafficking. Other layers such as the epithelium, Bowman layer, Descemet and endothelium are normal. Expressivity is highly variable with considerable asymmetry of opacities in the two eyes and even unilateral involvement.
Systemic Features
No systemic abnormalities have been reported.
Genetics
Inheritance
This is an autosomal dominant stromal dystrophy resulting from mutations in the PIKFYVE (PIP5K3) gene on chromosome 2 (2q35). A variety of missense, frameshift, and protein-truncating mutations have been found. The gene product is a member of the phosphoinositide 3-kinase family that regulates the synthesis, sorting, and transportation of intracellular multivesicular bodies.
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