Clinical and genetic heterogeneity of crystalline retinopathies: report of two families without bietti crystalline dystrophy.
OBJECTIVE
To report variations in the inheritance pattern and clinical presentation of crystalline retinopathies.


METHODS
Two different families with crystalline retinopathy were studied with a complete family history and ophthalmologic examination including Goldmann kinetic perimetry and electroretinography. Genetic studies were performed in one of the families.


RESULTS
One of the families had a clearly autosomal dominant mode of inheritance while the other family most likely follows an autosomal recessive pattern. Several members in each family had significant retinal pigment epithelial atrophy, intraretinal crystals, relatively pink optic nerves, and paracentral visual field defects, all of which are clinical features resembling those of Bietti crystalline retinopathy. Examination of peripheral leukocytes using transmission electron microscopy in selected affected members showed no evidence of classical lysosomal crystals that are characteristics for Bietti crystalline retinopathy. No pathogenic mutations were identified in the CYP4V2 gene.


CONCLUSIONS
Not all crystalline retinopathies are Bietti's. Further genetic, biochemical, and pathologic studies are required to better differentiate between these retinopathies.
From *Howard University Hospital, Washington, DC; and †Ophthalmic Genetics and Visual Function Branch, ‡Laboratory of Immunology, NEI, National Institutes of Health, Bethesda, Maryland.
O'Neil M
OM
Biscette
Rafael C
RC
Caruso
Nizar
N
Smaoui
Benjamin I
BI
Rubin
Mary Alice
MA
Crawford
Meira R
MR
Meltzer
Chi Chao
CC
Chan
Ekaterini
E
Tsilou