Retinoblastoma and polydactyly in a child with 46, XY, 15pstk+ karyotype—A case report and literature review

Background Retinoblastoma (Rb) is the most common intraocular malignancy in childhood, originating from primitive retinal stem cells or cone precursor cells. It can be triggered by mutations of the RB1 gene or amplification of the MYCN gene. Rb may rarely present with polydactyly. Methods We conducted karyotype analysis, copy number variation sequencing, and whole‐genome sequencing on the infant proband and his family. The clinical course and laboratory results of the proband's infant were documented and collected. We also reviewed the relevant literature. Results A 68‐day‐old boy presented with preaxial polydactyly and corneal edema. His intraocular pressure (IOP) was 40/19 mmHg, and color Doppler imaging revealed vitreous solid mass‐occupying lesions with calcification in the right eye. Ocular CT showed flaky high‐density and calcification in the right eye. This was classified as an International Retinoblastoma Staging System group E retinoblastoma with an indication for enucleation. Enucleation and orbital implantation were performed on the child's right eye. Karyotype analysis revealed an abnormal 46, XY, 15pstk+ karyotype, and the mother exhibited diploidy of the short arm of chromosome 15. The Alx‐4 development factor, 13q deletion syndrome, and the PAPA2 gene have been reported as potential mechanisms for Rb combined with polydactyly. Conclusion We report the case of a baby boy with Rb and polydactyly exhibiting a 46, XY, 15pstk+ Karyotype. We discuss potential genetic factors related to both Rb and polydactyly. Furthermore, there is a need for further exploration into the impact of chromosomal polymorphisms in Rb with polydactyly.