Study on relationship between delta 2642 genotypes in IT15 gene and age of onset of Huntington disease / 中华神经科杂志

ABSTRACT

Objective To detect the relationship between the genotypes of the 2642 deletion polymorphism (delta 2642) in IT15 gene and the age of onset of Huntington disease (HD). Methods Peripheral blood samples were collected from 29 patients with HD and 38 gender- and age-matched controls. All patients with HD were diagnosed by gene diagnosis. The CAG trinucleotide repeats of the 29 patients with HD outnumbered 40. Polymerase chain reaction-restriction fragment length polymorphism and polyacrylamide gel electrophoresis technique were used to detect the genotypes of delta 2642. Results No B/B genotype was detected in both 2 groups. The genotype frequencies of A/A and A/B in the IT15 delta 2642 polymorphism was 65.5% and 34. 5% in HD patients,92. 1% and 7. 9% in the controls respectively (x2 = 7. 435, P =0. 006). The frequency of the B allele was 17.2% in the HD group and 3. 9% in the control group (P = 0. 010, OR = 5.07, 95% CI 1.47-15.12). Analysis showed no significant difference between A/A genotype patients and A/B genotype patients for CAG trinucleotide repeats(P =0. 188). HD patients with A/B genotype (37.33±6. 46) had an earlier onset than the patients with A/A genotype (47.10± 10. 86, t = 2. 491, P = 0. 019). Conclusions These data demonstrated that variations in IT15 delta 2642 polymorphisms may be a genetic factor that influences the variability in HD age of onset. HD patients with delta 2642 A/B genotype have an earlier onset than the patients with A/A genotype.