Identification of single nucleotide polymorphism (SNP) 153104 (A to G) of RB1 gene in Malaysian retinoblastoma children and its association with laterality and staging of the disease

Abstract

Introduction: Retinoblastoma (Rb) is malignant eye tumors in childhood with majority of the cases are children under 4 years old. The gene associated with Rb is retinoblastoma susceptibility gene (RB1), a tumor suppressor gene which is located at chromosome 13q14. Although previous studies had reported polymorphisms in this gene, limited information is available on the Malaysian populations. A to G SNP at the nucleotide 153104 of RB1 gene was previously reported to be common only in Asian populations, with higher heterozygosity rates among the Southeast Asians. We conducted this study to determine the distribution of this SNP in Malaysian children with Rb and control subjects as well as its association with the laterality and staging of the disease. Study design: Allelic association study. Material and methods: Fourty-six children with confirmed cases of Rb by clinical presentation imaging or histopathology (37 Malays, 4 Chinese and 5 Indians) and equal number of healthy volunteers with ethnic-matched patients were included in this study. DNA was extracted from blood samples and used as template in PCR amplification. The amplicons were then digested with Tsp509I and visualized using 3% of agarose gel electrophoresis. Direct sequencing was performed to confirm the presence of SNP. Result: The SNP was found in 12 out of 46 patients (all Malays) and 6 out of 46 control subjects (frequency 0.13 and 0.07 respectively). Both groups conformed to Hardy-Weinberg expectation. There was no significant association of this SNP with laterality (p = 0.514) or disease staging (p = 1.000). Conclusion: We postulated that this SNP may not play role in susceptibility of individuals to the disease. To draw a right conclusion, enlarging the patient population study size in future could contribute towards a better understanding of the relationship of this SNP as an ethnic-specific marker with disease association. © 2010 Japan International Cultural Exchange Foundation.