title: Genetics of Bietti Crystalline Dystrophy.
abstract: Bietti crystalline dystrophy (BCD) is an inherited retinal degenerative disease characterized by crystalline deposits in the retina, followed by progressive atrophy of the retinal pigment epithelium (RPE), choriocapillaris, and photoreceptors. CYP4V2 has been identified as the causative gene for BCD. The CYP4V2 gene belongs to the cytochrome P450 superfamily and encodes for fatty acid ω-hydroxylase of both saturated and unsaturated fatty acids. The CYP4V2 protein is localized most abundantly within the endoplasmic reticulum in the RPE and is postulated to play a role in the physiological lipid recycling system between the RPE and photoreceptors to maintain visual function. Electroretinographic assessments have revealed progressive dysfunction of rod and cone photoreceptors in patients with BCD. Several genotypes have been associated with more severe phenotypes based on clinical and electrophysiological findings. With the advent of multimodal imaging with spectral domain optical coherence tomography, fundus autofluorescence, and adaptive optics scanning laser ophthalmoscopy, more precise delineation of BCD severity and progression is now possible, allowing for the potential future development of targets for gene therapy.
authors.affiliation: From the *Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong; and †2010 Retina and Macula Centre, Kowloon, Hong Kong.
authors.forename: Danny S C
authors.initials: DS
authors.lastname: Ng
authors.forename: Timothy Y Y
authors.initials: TY
authors.lastname: Lai
authors.forename: Tsz Kin
authors.initials: TK
authors.lastname: Ng
authors.forename: Chi Pui
authors.initials: CP
authors.lastname: Pang
mesh_terms: D003317:Corneal Dystrophies, Hereditary / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D042926:Cytochrome P-450 CYP4A / Q000378:metabolism / Q000502:physiology*; D000072470:Cytochrome P450 Family 4 / Q000235:genetics* / Q000502:physiology; D004596:Electroretinography; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006801:Humans; D009154:Mutation; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology; D012164:Retinal Diseases / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D055213:Retinal Pigment Epithelium / Q000378:metabolism; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology
chemical_list: C505357:CYP4V2 protein, human; D000072470:Cytochrome P450 Family 4; D042926:Cytochrome P-450 CYP4A