Clinical and molecular analysis of children with central pulverulent cataract from the Arabian Peninsula.

Aim: To clinically and genetically characterise central pulverulent cataract in a consecutive cohort of children from the Arabian Peninsula who were referred for ophthalmic evaluation.
Methods: Ophthalmic examination, homozygosity mapping in a consanguineous family and candidate gene analysis.
Results: All 16 children (4-16 years old, mean 9 years; seven girls and nine boys from 10 families) had bilateral central nuclear dust-like lenticular opacities. Two patients (one family) had cortical riders and six had associated strabismus. Cycloplegic retinoscopy was usually hyperopic (13/16; right eye spherical equivalent +0.50 to +6.25 dioptres, mean +3.50) but was sometimes myopic (3/16; right eye spherical equivalent -0.50 to -11.75, mean -6.50). In children with amblyopia (5/16), the cause was significant uncorrected ametropias rather than the lens opacities. Three patients had uncomplicated unilateral cataract surgery suggested by an outside second opinion that did not improve best-corrected visual acuity. Homozygosity mapping for one consanguineous family suggested the candidate gene CRYBB1. Sequencing of this gene revealed a homozygous c.171del mutation (p.N58Tfs*107) with a shared haplotype in all 16 children. In asymptomatic carrier parents from five of the six families available for careful slit-lamp examination, occasional central dot lenticular opacities were documented.
Conclusions: Central pulverulent cataract in this consanguineous population does not significantly impact visual acuity during early childhood, can be associated with significant ametropias (with amblyopia and/or strabismus) and is specific for a homozygous CRYBB1 founder mutation. Primary management in children is typically spectacle correction based on cycloplegic retinoscopy to treat significant refractive error rather than paediatric cataract surgery.