Bietti Crystalline Dystrophy

This 42YO female has been followed by us for 7 years with a known history of Bietti crystalline retinopathy with homozygosity for a pathogenic CYP4V2 variant. Vision was stable at 20/400 OU.

Fundus imaging shows extensive pigmentary degeneration with subretinal crystalline deposits involving both posterior poles. The crystalline deposits are best seen on near-infrared imaging. OCT scanning shows hyperreflective dots overlying the RPE-Bruch’s membrane complex with variable outer retinal and RPE loss. The pigmentary changes extend into each retinal periphery with more typical retinitis pigmentosa-like changes, including intraretinal pigment migration (bone spicules).

Learning Points:
Bietti crystalline dystrophy is an autosomal recessive ocular disorder that affects both the anterior and posterior segments. Clinical features include crystalline deposits in the retina, cornea, and rarely the crystalline lens, as well as retinal pigment epithelial clumping and atrophy. Mutations in CYP4V2 causing dysfunctional lipid metabolism have been implicated in its pathogenesis. While there are no definite treatments, anti-VEGF therapy can be given for secondary macular neovascularization. See Saatci et al for a recent review (Clinical Ophthalmology 2023;17:953-967).

This healthy 36YO female presented with a long history of bilateral vision loss with night blindness. Family history was negative. Vision was 20/80 bilaterally. Anterior segments were normal.

Fundus imaging shows extensive pigmentary degeneration with subretinal crystalline deposits involving both posterior poles. OCT scanning shows hyperreflective dots overlying the RPE-Bruch’s membrane complex with variable outer retinal and RPE loss. A few areas of outer retinal tubulation are noted temporally OS. Fundus autofluorescence (FAF) shows diffuse hypo-FAF throughout each posterior pole, dense hypo-FAF within areas of discrete atrophy, and dots of more peripheral hyper-FAF.

Learning Points:
Bietti crystalline dystrophy is an autosomal recessive ocular disorder that affects both the anterior and posterior segments. Clinical features include crystalline deposits in the retina, cornea, and rarely the crystalline lens, as well as retinal pigment epithelial clumping and atrophy. Mutations in CYP4V2 that cause dysregulated lipid metabolism have been implicated in its pathogenesis. While there is no definitive treatment, anti-VEGF therapy can be administered for secondary macular neovascularization. See Saatci et al for a recent review (Clinical Ophthalmology 2023;17:953-967).

This 28YO female has a known history of Bietti crystalline dystrophy and was without new visual complaints. Vision was 20/50 OD and 20/40 OS.

Fundus imaging of her right eye shows extensive subretinal crystalline deposits primarily in the posterior poles, with tiny subretinal pigment clumps more peripherally.

OCT scanning shows hyperreflective dots overlying the RPE-Bruch’s membrane complex, with variable outer retinal and RPE loss. Cystic changes are noted in the inner nuclear layer.

En face OCT through the outer retina reveals innumerable hyperreflective crystalline deposits. Identical findings were noted in her left eye.

Learning Points:
Bietti crystalline dystrophy is an autosomal recessive ocular disorder that affects both the anterior and posterior segments. Clinical features include crystalline deposits in the retina and cornea, and, rarely, in the crystalline lens, as well as retinal pigment epithelial clumping and atrophy.

Mutations in CYP4V2, which cause dysfunctional lipid metabolism, have been implicated in its pathogenesis. While there are no definite treatments, anti-VEGF therapy can be given for secondary macular neovascularization.

See Saatci et al for a recent review (Clinical Ophthalmology 2023;17:953-967).

This 28YO Egyptian male reported blurry vision, nyctalopia, and photosensitivity. His great-grandmother was blind from an unknown etiology. Vision was 20/40 OD and 20/60 OS.

Anterior segments were notable for bilateral limbal crystalline deposits (not shown). Fundus imaging shows extensive subretinal crystalline deposits primarily in the posterior poles bilaterally, with areas of subretinal fibrosis.

Fundus autofluorescence (FAF) shows central hypo-FAF with radiating dots of more peripheral hyper-FAF.

OCT scanning shows hyperreflective dots overlying the RPE-Bruch’s membrane complex, with variable outer retinal and RPE loss. A placoid area of subfoveal hyperreflectivity is also noted OS.

Genetic testing revealed pathogenic heterozygous CYP4V2 mutations, consistent with Bietti crystalline dystrophy.

Learning Points:
Bietti crystalline dystrophy is an autosomal recessive ocular disorder that affects both the anterior and posterior segments. Clinical features include crystalline deposits in the retina, cornea, and rarely the crystalline lens, as well as retinal pigment epithelial clumping and atrophy.

Mutations in CYP4V2, which cause dysfunctional lipid metabolism, have been implicated in its pathogenesis. While there is no definitive treatment, anti-VEGF therapy can be administered for secondary macular neovascularization. See Saatci et al for a recent review (Clinical Ophthalmology 2023;17:953-967).