OMIM ID:
Corneal Dystrophy, Gelatinous Drop-like
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
White, gelatinous deposits of amyloid are seen in the subepithelial region giving the surface of the cornea a multilobulated appearance resembling a mulberry. These usually appear in the first decade of life and cause photophobia as well as tearing from irritation caused by a severe foreign body sensation. The corneal changes are variable and some patients have only a mild amount of anterior stromal opacification while others have subepithelial vascularization. Vision loss can be severe when the deposits coalesce to opacify the cornea. These deposits are found in the subepithelial region but in some families it may also be found in the Bowman layer. The appearance of fusiform deposits in the stroma in some patients has led some to categorize gelatinous drop-like corneal dystrophy as a lattice dystrophy and have designated it as type III. GDLD seems to occur more commonly in Japan but often has a much later onset and the lattice appearance is more striking suggesting that it may be a unique form of corneal amyloidosis. True GDLD, however, occurs in diverse ethnic groups throughout the US, Europe, Latin America, and the Asian subcontinent. Cataracts have been reported in several young individuals with corneal amyloidosis.
Systemic Features
No systemic abnormalities occur as part of this syndrome.
Genetics
Inheritance
Autosomal recessive corneal amyloidosis results from multiple mutations in the M1S1 (TACSTD2) gene located on chromosome 1 (1p32).
Pedigree
Autosomal recessive
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.