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Govindasamy Kumaramanickavel, Sivasankar Malaichamy, Rohit Shetty, Arkasubhra Ghosh, Somasekar Seshagiri, Vedam L Ramprasad; Retinoblastoma and Next-Gen-Sequencing Era: Challenges and Opportunities at Clinics and Counseling in India. Invest. Ophthalmol. Vis. Sci. 2017;58(8):854.
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India accounts for the highest, about 20%, of the global burden of retinoblastoma (RB). We assessed how current molecular genetic technology is assisting and changing the landscape of RB clinical practice and counseling in a tertiary eye clinic in India.
In the present study, 51 children with RB underwent complete ophthalmic examination, clinical management and genetic analysis for germline status of the RB1 gene using targeted next generation sequencing (NGS) and multiplex ligation-dependent probe amplification (MLPA) techniques. The RB1 gene DNA libraries, from peripheral blood, were sequenced to mean >80-100X coverage on Illumina sequencing platform (HiSeq 2500). We used SALSA MLPA kit P047 RB1 (Amsterdam, Netherlands) as per manufacturer’s recommendations. Mutation and non-mutaion groups were analysed for disease recurrence, disease progression, histopathology types, clinical management and other clinical parameters. Appropriate ethical consents were obtained.
Thirty patients had bilateral RB (BLRB), twenty one had unilateral RB (ULRB) and two had familial history of RB. Average age of presentation was 1.8 years in BLRB and 2.3 years in ULRB. The genetic analysis revealed twenty nine variations (57%) in RB1 gene, including a novel mutation (7%), three variants with unknown significance (10%) and four heterozygous whole gene deletions (14%). The detection rates were 86% in BLRB and 18% in ULRB, on par with recent robust studies. Genotype–phenotype correlation showed an association of disease recurrence in genetic mutation group compared to the non-mutation group (p= 0.001). In a prenatal counseling, whole RBI gene maternal allele was detected in an unborn fetus.
In our study, mutation group had increased recurrence and mutation knowledge influenced clinical decisons like enucleation, increased frequency of periodic examination and radiotherapy was not advised for them. Clinical management and counseling (including prenatal) were influenced by the presence or absence of germline mutation, detected by the current NGS and MLPA molecuar genetic techniques. These techniques were important tools and the results were very useful to convice parents during clinical management and counseling.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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