Abstract
BackgroundPediatric cataract is an important cause of blindness and visual impairment in children. A large proportion of pediatric cataracts are inherited, and many genes have been described for this heterogeneous Mendelian disease. Surveys of schools for the blind in Bhutan, Cambodia, and Sri Lanka have identified many children with this condition and we aimed to identify the genetic causes of inherited cataract in these populations.MethodsWe screened, in parallel, 51 causative genes for inherited cataracts in 33 probands by Ampliseq enrichment and sequencing on an Ion Torrent PGM. Rare novel protein coding variants were assessed for segregation in family members, where possible, by Sanger sequencing.ResultsWe identified 24 rare (frequency <1% in public databases) or novel protein coding variants in 12 probands and confirmed segregation of variants with disease in the extended family where possible. Of these, six are predicted to be the cause of disease in the patient, with four other variants also highly likely to be pathogenic.ConclusionThis study found that 20%–30% of patients in these countries have a mutation in a known cataract causing gene, which is considerably lower than the 60%–70% reported in Caucasian cohorts. This suggests that additional cataract genes remain to be discovered in this cohort of Asian pediatric cataract patients.
Highlights
Pediatric cataract is an opacity of the ocular lens that is present at birth or develops during childhood
We investigated the genetic causes of cataract in children with suspected or known inherited cataract through screening of 51 genes known to cause this disease, using the same methodologies as applied to Australian pediatric cataract patients (Javadiyan et al, 2017)
Thirty-three probands with pediatric cataract were screened for mutations in the 51 reported cataract-causing genes
Summary
Pediatric cataract (including congenital cataract) is an opacity of the ocular lens that is present at birth (congenital) or develops during childhood. Analysis of panels of cataract-causing genes in patients with inherited cataract detect mutations in 60%–70% of patients (Gillespie et al, 2014; Javadiyan et al, 2017; Ma et al, 2016), but these studies have been undertaken in cohorts of patients predominantly of European descent Mutations in these same genes have been reported in patients from all over the world; large-scale gene screening has not yet been undertaken in patients with pediatric cataract from developing countries. Conclusion: This study found that 20%–30% of patients in these countries have a mutation in a known cataract causing gene, which is considerably lower than the 60%–70% reported in Caucasian cohorts. This suggests that additional cataract genes remain to be discovered in this cohort of Asian pediatric cataract patients
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