The Study On Polymorphism Of NUDT15 Gene Related To Thiopurine Metabolism In Yunnan Yi Nationality Children

ObjecTive:The myelotoxicity of mercaptopurine,which mainly is leukopenia,has been a difficult problem in clinical safety administration.Thiorpurine methyltransferase?TPMT?cannot fully explain the high incidence of thiopurine-induced bone marrow toxicity in Asians.It was first to be found in 2014 that nucleoside diphophate-linked moiety X-type motif 15?NUDT15?is closely associated with thiopurine-induced leukopenia in patients with inflammatory bowel disease.Subsequently,NUDT15 was found to be associated with mercaptopurine tolerance and myelosuppression in patients with acute lymphoblastic leukemia?ALL?,especially in Asians.In this subject,we will study the genetic polymorphisms of NUDT15 of healthy Yi nationality children in Yunnan province,and analyze the frequency distribution of alleles,in order to find out whether there are new mutation sites.MeThods:120 healthy children?between 5 and 12 years old?who are the Yi nationality within the three generations in Yunnan province.Every one was collected 3mL peripheral blood.Then we will collect data by DNA extraction,PCR amplification and gene sequencing technology to test the exon 1-3 of NUDT15 gene.ResulTs:1.One hundred and twenty healthy children children of Yunnan province were between 5 and 12 years old,including 67 boys and 53 girls.Among them,two variants were found in NUDT15 Exonl,which were rs186364861?c.416G>A,encoding Arg139His?and rs554405994?c.36₃7insGGAGTC,encoding p.Vall8_Val19insGlyVal?,and 4 cases of them were rs186364861,accounting for 3.33%,and 26 cases of them were rs554405994,accounting for 21.67%.There were 90 cases of wild-type without mutations,accounting for 75.00%.2.One variant was found in NUDT15 Exon3 in 120 healthy children from the Yunnan Yi nationality,namely rs116855232?c.415C>T,encoding p.Arg139Cys?.3.The allele of NUDT15 rs116855232 was T/C.and one homozygous TT genotype was tested,accounting for 0.8%.Heterozygous TC genotype was found in 18 cases,accounting for 15.0%.The wild-type CC was found in 101 cases,accounting for 84.2%,and the frequency of risk allelic mutation was 8.3%.Conclusion?s?:1.Three common mutated forms of NUDT15 gene were found in children of healthy Yi nationality children in Yunnan province:rsl86364861?c.416G>A,coding Arg139His?,rs554405994?c.36₃7insGGAGTC,coding p.Val18_Val19insGlyVal?,and rs116855232?c.415C>T,encoding p.Arg139Cys?,and there were no new mutation sites were found.2.The frequency of rsl 16855232 mutation allele in Yunnan Yi children was 8.3%,which was not different from those in Taiwan?11.6%?,Han nationality of Guangdong province?12.1%?,Koreans?12.1%?,and Indians?10.7%?,and the genotype distribution was similar.The frequency of mutation was lower than Han nationality children of Shanghai in China?13.1%?and Janpenese?17.3%or 16.3%?.The distribution of genotypes was different from the Han nationality of Shanghai.3.This study showed that wild-type CC was the most common among Yunnan Yi nationality children in the NUDT15 exon3.Heterozygous mutation of TC genotype was the second,and homozygous mutation of TT genotype was the rarest.4.The frequency of mutation allele of NUDT15 Exonl-3 samples from healthy Yi nationality children in Yunnan province are independent of gender.5.The polymorphic data of NUDT15 gene of Yunnan Yi nationality healthy children filled the vacancy of ethnic minorities?Yi nationality?in China.