Childhood Cataract

Infantile cataract is a significant cause of childhood blindness. The prevalence of congenital cataract is reported between 1 and 3 per 10,000 children. Early detection and prompt treatment are necessary to avoid severe visual loss. Depending on the severity of the cataract, treatment may include pharmacologic pupil dilatation, occlusion therapy, correction of refractive errors, and/or cataract surgery. Visual rehabilitation is required after the cataract surgery in young children. Recognizing the genetic etiology of a childhood cataract may be facilitated by careful attention to the cataract morphology such as anterior lenticonus in Alport syndrome, anterior pyramidal cataract in PAX6 mutations, embryonal or fetal nuclear, cerulean, Coppock cataract, sutural, posterior subcapsular, and others. A unilateral cataract due to persistent fetal vasculature (PFV) is usually not due to a known germline genetic cause. Excellent reviews have been published on the systemic associations with cataract, which may also guide the genetic evaluation. One must also consider the nongenetic causes of cataract including intrauterine infection, trauma, steroids, uveitis, and radiation.


10.2 Molecular Genetics


Approximately 50% of congenital cataract cases have genetic causes. Autosomal dominant (AD), autosomal recessive (AR), and X-linked inheritance patterns have been described, with AD being the most frequent. Mutations in transcription factor genes, developmental genes, genes required in lens development, and lens crystallin genes can cause cataract. ▶ Table 10.1 illustrates examples from these categories. To date, for nonsyndromic cataract, at least 45 loci have been mapped and 38 genes identified.






















































































































































































































































































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Apr 7, 2019 | Posted by in OPHTHALMOLOGY | Comments Off on Childhood Cataract

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Table 10.1 Summary of genes/loci associated with isolated cataract

Cataract description and morphology


Phenotype name (MIM number)


Gene/locus (MIM number)


Chromosome


Inheritance


Other association


Volkmann type (progressive, central, or zonular, with opacities in the embryonic, fetal, and juvenile nucleus and around the anterior and posterior Y-suture)


Cataract 8, multiple types; CTRCT8 (115665)


CTRCT8 (–)


1pter-p36.13


AD



Posterior polar, congenital total, complete, age-related cortical


Cataract 6, multiple types; CTRCT6 (116600)


EPHA2D (176946)


1p36.13


AD


Myopia


Membranous and posterior capsular


Cataract 34, multiple types; CTRCT34 (612968)


CTRCT34 (–)


1p34.3-p32.2


AR


Corneal opacity, microcornea


Congenital, zonular pulverulent, nuclear, nuclear pulverulent, stellate nuclear, nuclear total, total, and posterior subcapsular


Cataract 1, multiple types; CTRCT1 (116200)


CX50, GJA8G (600897)


1q21.2


AD


Cataract-microcornea syndrome


Crystalline coralliform (multiple coral-like white opacities)


Cataract 29; CTRCT29 (115800)


CTRCT29 (–)


2pter-p24


AD



Aculeiform, crystalline aculeiform, crystalline, crystal, frosted, needle-shaped, fasciculiform, congenital cerulean, nonnuclear polymorphic congenital, central nuclear, lamellar, and punctate


Cataract 4, multiple types; CTRCT4 (115700)


CRYGDC (123690)


2q33.3


AD



Coppock-like; embryonic, fetal, infantile nuclear; zonular pulverulent; and lamellar


Cataract 2, multiple types; CTRCT2 (604307)


GRYGC (123680)


2q33.3


AD


Microcornea


Congenital lamellar, anterior polar, and complete


Cataract 39, multiple types; CTRCT39 (615188)


CRYGBC (123670)


2q33.3


AD



Multifocal congenital


Cataract 42; CTRCT42 (115900)


CRYBA2C (600836)


2q35


AD


Eccentric pupil, myopia


Congenital and congenital nuclear


Cataract 18; CTRCT 18 (610019)


FYCO1G (607182)


3p21.31


AR



Congenital nuclear, sutural, stellate cortical; Juvenile-onset lamellar, cortical, nuclear embryonic, or Y-sutural; and adult-onset punctate cortical


Cataract 12, multiple types; CTRCT12 (611597)


BFSP2G (603212)


3q22.1


AD



Progressive polymorphic anterior, posterior, or peripheral cortical, membranous


Cataract 20, multiple types; CTRCT20 (116100)


CRYGSC (123730)


3q27.3


AD



Congenital nuclear


Cataract 41 (116400)


WFS1G (606201)


4p16.1


AD



Congenital, total


Cataract 13 with adult i phenotype (116700)


GCNT2G (600429)


6p24.3-p24.2


AD


i-negative and i-positive red blood type


Cortical, age related


Cataract 28, age related, cortical, susceptibility to; CTRCT28 (609026)


ARCC1G (–)


6p12-q12




Congenital


Cataract 38; CTRCT38 (614691)


AGKG (610345)


7q34


AR


Sengers syndrome


Cortical, pulverulent, nuclear, and posterior subcapsular


Cataract 26, multiple types; CTRCT26 (605749)


CAAR (–)


9q13-q22


AR



Congenital, or juvenile cataract


Cataract 36; CTRCT36 (613887)


TDRD7D (611258)


9q22.33


AR



Pulverulent, nuclear


Cataract 30, pulverulent; CTRCT30 (116300)


VIMG (193060)


10p13


AD



Congenital total and posterior polar


Cataract 11, multiple types; cataract 11, syndromic; CTRCT11 (610623)


PITX3T (602669)


10q24.32


AD


Microphthalmia, neurodevelopmental abnormalities


Congenital posterior polar, congenital lamellar, nuclear, complete, and juvenile


Cataract 16, multiple types; CTRCT16 (613763)


CRYABC (123590)


11q23.1


AR, AD


Myofibrillar myopathy, dilated cardiomyopathy


Polymorphic, progressive punctate lamellar, cortical, anterior and posterior polar, nonprogressive lamellar with sutural opacities, embryonic nuclear, and pulverulent cortical


Cataract 15, multiple types; CTRCT15 (615274)


MIPG (154050)


12q13.3


AD



Cerulean, cuneiform


Cataract 37; CTRCT37 (614422)


CCA5 (–)


12q24.2-q24.3


AD



Zonular pulverulent, posterior polar, nuclear coralliform, embryonal nuclear, and Coppock-like


Cataract 14, multiple types; CTRCT14 (601885)


GJA3G (121015)


13q12.11


AD



Anterior polar, or posterior polar


Cataract 32, multiple types; CTRCT32 (115650)


CTAA1 (–)


14q22-q23


AD



Central pouchlike cataract with sutural opacities


Cataract 25; CTRCT25 (605728)


CCSSO (–)


15q21-q22


AD



Infantile, lamellar, zonular, nuclear, anterior polar, stellate, pulverulent and Marner type


Cataract 5, multiple types; CTRCT5 (116800)


HSF4T (602438)


16q22.1


AD



Juvenile cortical pulverulent and later progression of posterior subcapsular, congenital cerulean, lamellar, anterior polar, nuclear, poster polar, anterior subcapsular and stellate


Cataract 21, multiple types; CTRCT21 (610202)


MAFT (177075)


16q23.2


AD


Microcornea, iris coloboma, macular hypoplasia (rare)


Anterior polar


Cataract 24, anterior polar; CTRCT24 (601202)


CTAA2 (–)


17p13


AD



Congenital zonular with sutural opacities, congenital nuclear progressive, and progressive lamellar; Y-shaped sutural


Cataract 10, multiple types; CTRCT10 (600881)


CRYBA1C (123610)


17q11.2


AD



Posterior subcapsular and central


Cataract 43; CTRCT43 (616279)


UNC45B (611220)


17q12


AD



Cerulean cataract


Cataract 7; CTRCT7 (115660)


CCA1 (–)


17q24


AD



Congenital nuclear cataract


Cataract 35, congenital nuclear; CTRCT35 (609376)


CATCN1 (–)


19q13


AR



Congenital dense white


Cataract 45; CTRCT45 (616851)


SIPA1L3 (616655)


19q13.1-q13.2


AR



Late-onset cortical pulverulent; congenital total


Cataract 19, multiple types; CTRCT19 (615277)


LIM2G (154045)


19q13.41


AR



Fluffy, cottonlike cortical; grapelike cysts in the anterior cortex


Cataract 33; CTRCT33 (611391)


BFSP1G (603307)


20p12.1


AR



Posterior polar, progressive posterior subcapsular, nuclear, and anterior subcapsular


Cataract 31, multiple types; CTRCT31 (605387)


CHMP4BG (–)


20q11.22


AD