[Retinoblastoma in Argentina: study of germline variants of the RB1 gene]

Retinoblastoma is an embryonal origin neoplasm of the developing retina. It represents the most frequent ocular cancer in childhood. The presentation can be unilateral, bilateral or trilateral. In patients with bilateral retinoblastoma, germline variants in the RB1 gene are observed in approximately 90%, while in unilateral retinoblastoma in 10-25% of cases. Molecular study is essential for familial genetic counseling.

Sixty patients with retinoblastoma who consulted Garrahan Hospital between 2018-2022 were evaluated. For the study of single nucleotide variants, PCR amplification and Sanger sequencing of the RB1 gene was performed. Multiplex Ligationdependent Probe Amplification was used to detect copy number alterations.

Of the 60 patients, 22 single nucleotide variants and 6 heterozygous deletions were detected in bilateral retinoblastoma (n:32). In 2 patients with unilateral retinoblastoma (n:28) alterations were observed, being in one case a single nucleotide variant and in the other a deletion of the whole gene. Family segregation and genetic counseling were performed when feasible.

This study allowed us to describe the genetic variants of the RB1 gene in Argentine pediatric patients with retinoblastoma. The distribution and types of variants observed in this patient group are similar to those described in other populations. Currently, next-generation sequencing is in the process of being incorporated in order to describe variants with higher throughput technology.