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Bietti crystalline corneoretinal dystrophy(BCD)

MedGen UID:
Concept ID:
Disease or Syndrome
Synonyms: BCD; Bietti Crystalline Dystrophy; Bietti tapetoretinal degeneration with marginal corneal dystrophy
SNOMED CT: Bietti crystalline retinopathy (312927001); Bietti's crystalline retinopathy (312927001)
Modes of inheritance:
Autosomal recessive inheritance
MedGen UID:
Concept ID:
Intellectual Product
Source: Orphanet
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele).
Gene (location): CYP4V2 (4q35.1-35.2)
Monarch Initiative: MONDO:0008865
OMIM®: 210370
Orphanet: ORPHA41751

Disease characteristics

Excerpted from the GeneReview: Bietti Crystalline Dystrophy
Bietti crystalline dystrophy (BCD) is a chorioretinal degeneration characterized by the presence of yellow-white crystals and/or complex lipid deposits in the retina and (to a variable degree) the cornea. Progressive atrophy and degeneration of the retinal pigment epithelium (RPE) / choroid lead to symptoms similar to those of other forms of retinal degeneration that fall under the category of retinitis pigmentosa and allied disorders, namely: reduced visual acuity, poor night vision, abnormal retinal electrophysiology, visual field loss, and often impaired color vision. Marked asymmetry between eyes is not uncommon. Onset is typically during the second to third decade of life, but ranges from the early teenage years to beyond the third decade. With time, loss of peripheral visual field, central acuity, or both result in legal blindness in most if not all affected individuals. [from GeneReviews]
Mauricio Vargas  |  Amanda Mitchell  |  Paul Yang, et. al.   view full author information

Additional descriptions

Bietti crystalline corneoretinal dystrophy is an autosomal recessive retinal dystrophy characterized by numerous tiny glistening yellow-white crystals at the posterior pole of the retina, associated with atrophy of the retinal pigment epithelium (RPE), pigment clumps, and choroidal sclerosis. Most cases have similar crystals at the corneoscleral limbus. The disorder is progressive; most patients develop decreased vision, nyctalopia, and paracentral scotomata between the second and fourth decades of life. Patients later develop peripheral visual field loss and marked visual impairment, usually progressing to legal blindness by the fifth or sixth decade of life. In a series of European patients diagnosed with nonsyndromic retinitis pigmentosa (RP; see 268000), BCD accounted for approximately 3% of all nonsyndromic RP and 10% of nonsyndromic autosomal recessive RP. Histopathology shows advanced panchorioretinal atrophy, with crystals and complex lipid inclusions seen in choroidal fibroblasts, corneal keratocytes, and conjunctival and skin fibroblasts, as well as in circulating lymphocytes, suggesting that BCD may result from a systemic abnormality of lipid metabolism (summary by Li et al., 2004).  http://www.omim.org/entry/210370
From MedlinePlus Genetics
Bietti crystalline dystrophy is a disorder in which numerous small, yellow or white crystal-like deposits of fatty (lipid) compounds accumulate in the light-sensitive tissue that lines the back of the eye (the retina). The deposits damage the retina, resulting in progressive vision loss.

People with Bietti crystalline dystrophy typically begin noticing vision problems in their teens or twenties. They experience a loss of sharp vision (reduction in visual acuity) and difficulty seeing in dim light (night blindness). They usually lose areas of vision (visual field loss), most often side (peripheral) vision. Color vision may also be impaired.

The vision problems may worsen at different rates in each eye, and the severity and progression of symptoms varies widely among affected individuals, even within the same family. However, most people with this condition become legally blind by their forties or fifties. Most affected individuals retain some degree of vision, usually in the center of the visual field, although it is typically blurry and cannot be corrected by glasses or contact lenses. Vision impairment that cannot be improved with corrective lenses is called low vision.  https://medlineplus.gov/genetics/condition/bietti-crystalline-dystrophy

Clinical features

From HPO
Retinal degeneration
MedGen UID:
Concept ID:
A nonspecific term denoting degeneration of the retinal pigment epithelium and/or retinal photoreceptor cells.
Reduced visual acuity
MedGen UID:
Concept ID:
Diminished clarity of vision.
Constriction of peripheral visual field
MedGen UID:
Concept ID:
An absolute or relative decrease in retinal sensitivity extending from edge (periphery) of the visual field in a concentric pattern. The visual field is the area that is perceived simultaneously by a fixating eye.
High myopia
MedGen UID:
Concept ID:
Disease or Syndrome
A severe form of myopia with greater than -6.00 diopters.
Paracentral scotoma
MedGen UID:
Concept ID:
Corneal crystals
MedGen UID:
Concept ID:
Pathologic Function
Progressive visual loss
MedGen UID:
Concept ID:
A reduction of previously attained ability to see.
Marginal corneal dystrophy
MedGen UID:
Concept ID:
Disease or Syndrome
Progressive night blindness
MedGen UID:
Concept ID:
Chorioretinal atrophy
MedGen UID:
Concept ID:
Disease or Syndrome
Atrophy of the choroid and retinal layers of the fundus.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVBietti crystalline corneoretinal dystrophy
Follow this link to review classifications for Bietti crystalline corneoretinal dystrophy in Orphanet.

Professional guidelines


Dai H, Zhang Y, Li R, Li Y, Li G
Curr Eye Res 2022 Mar;47(3):436-442. Epub 2021 Nov 2 doi: 10.1080/02713683.2021.1995004. PMID: 34724870
Meng XH, He Y, Zhao TT, Li SY, Liu Y, Yin ZQ
Mol Vis 2019;25:654-662. Epub 2019 Oct 31 PMID: 31741654Free PMC Article

Recent clinical studies


Wang Y, Guo L, Cai SP, Dai M, Yang Q, Yu W, Yan N, Zhou X, Fu J, Guo X, Han P, Wang J, Liu X
PLoS One 2012;7(5):e33673. Epub 2012 May 31 doi: 10.1371/journal.pone.0033673. PMID: 22693542Free PMC Article


Wang T, Chen Q, Yao X, Kuang L, Gan R, Wang J, Yan X
Gene 2021 Jul 20;790:145698. Epub 2021 May 5 doi: 10.1016/j.gene.2021.145698. PMID: 33964374
Jiao X, Li A, Jin ZB, Wang X, Iannaccone A, Traboulsi EI, Gorin MB, Simonelli F, Hejtmancik JF
Eur J Hum Genet 2017 Apr;25(4):461-471. Epub 2017 Jan 4 doi: 10.1038/ejhg.2016.184. PMID: 28051075Free PMC Article
Yin X, Yang L, Chen N, Cui H, Zhao L, Feng L, Li A, Zhang H, Ma Z, Li G
Exp Eye Res 2016 May;146:154-162. Epub 2016 Mar 10 doi: 10.1016/j.exer.2016.03.007. PMID: 26971461
Bozkurt B, Ozturk BT, Kerimoglu H, Irkec M, Pekel H
Cornea 2010 May;29(5):590-3. doi: 10.1097/ICO.0b013e3181be22ee. PMID: 20299976
Nakamura M, Lin J, Nishiguchi K, Kondo M, Sugita J, Miyake Y
Adv Exp Med Biol 2006;572:49-53. doi: 10.1007/0-387-32442-9_8. PMID: 17249554


Bozkurt B, Ozturk BT, Kerimoglu H, Irkec M, Pekel H
Cornea 2010 May;29(5):590-3. doi: 10.1097/ICO.0b013e3181be22ee. PMID: 20299976


Song WK, Clouston P, MacLaren RE
Ophthalmic Genet 2019 Oct;40(5):461-465. Epub 2019 Oct 22 doi: 10.1080/13816810.2019.1678176. PMID: 31638456
Yin X, Yang L, Chen N, Cui H, Zhao L, Feng L, Li A, Zhang H, Ma Z, Li G
Exp Eye Res 2016 May;146:154-162. Epub 2016 Mar 10 doi: 10.1016/j.exer.2016.03.007. PMID: 26971461
Lin J, Nishiguchi KM, Nakamura M, Dryja TP, Berson EL, Miyake Y
J Med Genet 2005 Jun;42(6):e38. doi: 10.1136/jmg.2004.029066. PMID: 15937078Free PMC Article

Clinical prediction guides

Yin X, Yang L, Chen N, Cui H, Zhao L, Feng L, Li A, Zhang H, Ma Z, Li G
Exp Eye Res 2016 May;146:154-162. Epub 2016 Mar 10 doi: 10.1016/j.exer.2016.03.007. PMID: 26971461
Song Y, Mo G, Yin G
Int Ophthalmol 2013 Jun;33(3):269-76. Epub 2012 Dec 14 doi: 10.1007/s10792-012-9686-2. PMID: 23242590
Jiao X, Munier FL, Iwata F, Hayakawa M, Kanai A, Lee J, Schorderet DF, Chen MS, Kaiser-Kupfer M, Hejtmancik JF
Am J Hum Genet 2000 Nov;67(5):1309-13. Epub 2000 Sep 21 doi: 10.1016/S0002-9297(07)62960-7. PMID: 11001583Free PMC Article

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