Abstract
Purpose :
An isolated form of congenital cataract associated with macular hypoplasia and foveal hypoplasia was observed in four members of a German family. Clinical features were compared and described in detail, and genetic testing was performed.
Methods :
The mother (index patient) and her three affected children were examined including slit lamp examination, funduscopy, and macular structure assessment using SD-OCT and OCTA. Gene panel analysis for cataract (COL4A1 , CRYAA, CRYAB, CRYBB1, CRYBB3, CRYGC, FOXE3, GJA3, GJA8, HSF4, LIM2, NHS, SIL1), macular hypoplasia (OA1) or both (PAX6) is performed by NGS.
Results :
Anterior segment showed pseudophakia in the 40-year-old index patient (#1), spectacle corrected aphakia in the youngest, 7-year-old son (#4), mild anterior lens opacities in both the 10-year-old twins (#2, #3) as well as wedge-shaped peripheral cataracts in the twin daughter (#3). Iris was normal with no detectable transillumination defects in any of the subjects. Nystagmus was visible in #1, #4, absent in the twins (#2, #3). Strabismus with reduced stereoscopic vision was present in #1, #4 (microesotropia) and #2 (microexotropia). Refractive error ranged from moderate astigmatism (#1) over mild to moderate hyperopic astigmatism (#3, #4) to high hyperopia (#2). Snellen BCVA ranged from 0.7 OU (#1), 0.6 OU (#2) to 0.5 OD (#3, #4) and 0.6 OS (#3) or 0.7 OS (#4). Fundus examination revealed a macular wall reflex in all subjects with a mild to moderate foveal ectopia below the midline. Optic discs were remarkable for mild elevation in #1 (grayish color) and #3 (hyperemia), unremarkable in #2, #4. SD-OCT of the optic discs revealed a temporal RNFL reduction in all three children, while SD-OCT of the fovea showed a grade 2 foveal hypoplasia in all four subjects. OCT-A revealed a smaller (#3, #4) or absent foveal avascular zone (#1, #2) and showed flow in the foveal pit. Family history suggests autosomal dominant inheritance of the disorder.
Conclusions :
The combination of cataract, macular hypoplasia and nystagmus is rare. We describe four affected members of a German family, including a pair of twins, with no apparent iris transillumination defects or additional features of albinism or inherited aniridia. Genetic testing of known genes associated with the observed phenotype is expected to either identify the cause of disease or define a novel locus for autosomal dominant congenital cataract.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.