<p>Current perspectives in Bietti crystalline dystrophy</p>

Abstract

Bietti crystalline dystrophy (BCD) is a rare-inherited disease caused by mutations in the CYP4V2 gene and characterized by the presence of multiple shimmering yellow-white deposits in the posterior pole of the retina in association with atrophy of the retinal pigment epithelium (RPE) and chorioretinal atrophy. The additional presence of glittering dots located at the corneal limbus is also a frequent finding. The CYP4V2 protein belongs to the cytochrome P450 subfamily 4 and is mainly expressed in the retina and the RPE and less expressed in the cornea. The disease has its metabolic origin in the diminished transformation of fatty acid substrates into n-3 polyunsaturated fatty acids due to a dysregulation of the lipid metabolism. In this review, we provide updated insights on clinical and molecular characteristics of BCD including underlying mechanisms of BCD, genetic diagnosis, progress in the identification of causative genetic and epigenetic factors, available techniques of exploration and development of novel therapies. This information will help clinicians to improve accuracy of BCD diagnosis, providing the patient reliable information regarding prognosis and clinical prediction of the disease course.

Predicted Protein Structure Variations Indicate the Clinical Presentation of Cyp4v2-Related Bietti Crystalline Dystrophy

“…[13][14][15] In addition to the high prevalence, c.802-8_810del17insGC has also been associated with a relatively early disease onset and more severe phenotype. 13,16 Because many novel CYP4V2 variants have been reported, some researchers have tried to predict the pathogenic effects of variants through protein structure analysis 5,17,18 ; however, clear genotype-phenotype correlations have not been well established. 13,16,19 Phenotype characteristics and severity have been reported to vary widely among patients, but they have not been correlated with age.…”

Structural and functional phenotypic features and molecular analysis of Indian patients with Bietti crystalline dystrophy

“…The limbal corneal crystals are very fine and often very subtle and therefore are likely to be missed even by experienced specialists. [ 1 4 ] However, it is also noted by some authors that the corneal crystals are absent in Asian populations but more commonly seen in Caucasian populations. [ 15 19 ] The CYP4V2 coded protein is less expressed in the corneal epithelium than the RPE.…”

“…Bietti crystalline dystrophy (BCD) is a rare form of inherited retinal dystrophy, first described by Prof. Gian Battista Bietti in 1937. [ 1 ] It is known to affect about 1 in 67,000 persons and is more prevalently seen in the East Asian people, mostly in the Chinese population. [ 2 ] It starts in early childhood.…”

“…BCD is increasingly being described in populations other than the Chinese, such as the Japanese, Spanish, Middle Eastern, Brazilian, and Nepalese. [ 1 4 ] There are a few isolated case reports from the Indian population as well. [ 6 7 ] This is the largest study so far reported from the Indian population.…”

CHM mutation spectrum and disease: An update at the time of human therapeutic trials

“…Choroideremia should be distinguished from other chorioretinal dystrophies inherited as either an autosomal recessive or dominant trait. Among the recessive chorioretinal disorders are gyrate atrophy (MIM# 258870), which is linked to mutations in OAT (MIM# 613349), encoding the ornithine aminotransferase and associated with hyperornithinemia, (Hayasaka et al, 1985), and Bietti crystalline dystrophy (MIM# 210370) linked to mutations in CYP4V2 (MIM# 608614; Garcia‐Garcia et al, 2019). Among the autosomal dominant chorioretinal diseases are RPE65 ‐related dystrophy (MIM# 618697; Bowne et al, 2011), late‐onset retinal degeneration (LORD; MIM# 605670) linked to mutations in C1QTNF5 (MIM# 608752; Hayward et al, 2003), and one specific mutation in RHO (Audo et al, 2010).…”