RETINOBLASTOMA SUSCEPTIBILITY GENE (RB1) POLYMORPHISM AMONG CHILDREN IN CALABAR, NIGERIA

Mary E. Kooffreh*, Roseline Duke, Nkoyo Ephraim and Anthony Umoyen

ABSTRACT

Retinoblastoma is an eye disease causing blindness and death in children. The screening of the RB1 gene in retinoblastoma children, relatives and controls lead to the documentation of more than 900 mutations in different populations, which are important for genetic counselling, characterization of phenotypic-genotypic relationships and clinical management of the disease. There is no information on the RB1 gene polymorphism among retinoblastoma children in Calabar, Nigeria. This study investigated the genetic polymorphism of RB1 susceptibility gene and its involvement in the molecular pathogenesis of retinoblastoma in Calabar. This research was carried out in the University of Calabar Teaching Hospital (UCTH) Calabar, Nigeria. Blood was collected from 9 clinically diagnosed retinoblastoma children, 30 children and 23 adults as controls. DNA was extracted from all the blood samples, PCR was performed yielding a 485bp amplicon that was digested using the M1u CI restriction enzyme. The digested fragments were visualized in 1.5% agarose and the genotype and allele frequency was determined. The genotype frequencies among the retinoblastoma children were 0(0%), 3(33.33%) and 6(66.67%) and in the controls were 0(0%), 13(24.53%) and 40(75.47%) for GG, GA and AA respectively. The G allele was low (0.17and 0.12 in patients and controls). There were no significant differences in the genotypic proportions of the RB1 gene polymorphism among patients and controls. The RB1 gene polymorphism may not be directly involved in the development of retinoblastoma however this requires further investigation.

Keywords: Retinoblastoma, Children, Gene Polymorphism, RB1, Calabar.