Overview
Gene (OMIM No.) |
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Function of gene/protein |
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Clinical phenotype (OMIM phenotype no.) |
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Inheritance |
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Ocular features |
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Systemic features |
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Key investigations |
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Molecular diagnosis | Next generation sequencing
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Management | Ocular |
Therapies under research |
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Further information |
Additional information
In the first pedigree of autosomal dominant congenital cerulean cataract reported by Bodker et al and subsequently by Kramer et al, a female (individual #102) who was product of a consanguineous marriage between two affected cousins, displayed congenital cataract, microphthalmia and microcornea.[3,4] All other affected family members only had isolated cataract with mild visual symptoms in their childhood and early adolescence. Individual #102 required cataract extraction at age 5 years and loss her vision later in adulthood due to bilateral band keratopathy and corneal neovascularisation. Litt et al later identified that she harboured a homozygous truncating p.Gln155Ter mutation while the other affected family members were heterozygous, thus representing a rare example of homozygosity for a dominant mutation.[5]
References
- Bateman JB, von-Bischhoffshaunsen FR, Richter L, Flodman P, Burch D, Spence MA. Gene conversion mutation in crystallin, beta-B2 (CRYBB2) in a Chilean family with autosomal dominant cataract. Ophthalmology. 2007;114(3):425‐432
- Bijlsma EK, Delattre O, Juyn JA, et al. Regional fine mapping of the beta crystallin genes on chromosome 22 excludes these genes as physically linked markers for neurofibromatosis type 2. Genes Chromosomes Cancer. 1993;8(2):112‐118
- Bodker FS, Lavery MA, Mitchell TN, Lovrien EW, Maumenee IH. Microphthalmos in the presumed homozygous offspring of a first cousin marriage and linkage analysis of a locus in a family with autosomal dominant cerulean congenital cataracts. Am J Med Genet. 1990;37(1):54‐59
- Kramer P, Yount J, Mitchell T, et al. A second gene for cerulean cataracts maps to the beta crystallin region on chromosome 22. Genomics. 1996;35(3):539‐542
- Litt M, Carrero-Valenzuela R, LaMorticella DM, et al. Autosomal dominant cerulean cataract is associated with a chain termination mutation in the human beta-crystallin gene CRYBB2. Hum Mol Genet. 1997;6(5):665‐668
- Gill D, Klose R, Munier FL, et al. Genetic heterogeneity of the Coppock-like cataract: a mutation in CRYBB2 on chromosome 22q11.2. Invest Ophthalmol Vis Sci. 2000;41(1):159‐165
- Kerscher S, Church RL, Boyd Y, Lyon MF. Mapping of four mouse genes encoding eye lens-specific structural, gap junction, and integral membrane proteins: Cryba1 (crystallin beta A3/A1), Crybb2 (crystallin beta B2), Gja8 (MP70), and Lim2 (MP19). Genomics. 1995;29(2):445‐450