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Singh M, Bhaskar D, Bhatia P, Thakur R, Sharma P, Bansal D, Jain R, Trehan A. Evaluation of FTO polymorphism in 6-mercaptopurine related intolerance in children with acute lymphoblastic leukemia. Cancer Chemother Pharmacol 2023; 92:51-56. [PMID: 37256334 DOI: 10.1007/s00280-023-04546-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 05/17/2023] [Indexed: 06/01/2023]
Abstract
PURPOSE Thiopurine drugs like 6-Mercaptopurine (6MP) are the cornerstone of maintenance therapy in acute lymphoblastic leukemia (ALL). A recently described variant in alpha-ketoglutarate dependent dioxygenase (FTO) gene has been reported to play an important role in thiopurine induced myelosuppression. METHODS In this study, we genotyped a coding variant (p.Ala134Thr, rs79206939) and an intronic variant (rs16952570) of FTO in 174 Indian children (age ≤ 12 years) with ALL on maintenance phase of chemotherapy and examined correlation with the risk of thiopurine induced myelosuppression and hepatic toxicity. RESULTS The prevalence of FTO-rs16952570 polymorphism was 18.4% (32/174) with 142 (82%) cases having TT genotype, 26 (15%) cases with TC genotype and 6 (3.4%) cases having CC genotype. FTO-rs79206939 was absent and non-polymorphic in our study group. The mean dose of 6-MP during 36 weeks of maintenance of TT, TC and CC carriers of FTO-rs16952570 was 53.7, 53.6 and 54.1 mg/m2/day. Number of patients tolerating starting dose of 60 mg/m2/day was significantly higher in CC (50%) than TT/TC (14%) genotype carrying cases (p = 0.014). However, no statistical significance was observed for total leukocyte count (TLC), absolute neutrophil count (ANC) as well as for platelets counts in patients harboring FTO-rs16952570 TT/TC/CC genotype at 4, 8, 12, 24 and 36 weeks after start of thiopurine therapy. Further, no significant correlation was noted between number of weeks of chemotherapy interruptions or episodes of febrile neutropenia and no evidence of hepatotoxicity was found with the genotype studied. CONCLUSION Polymorphism in FTO-rs16952570 did not show any correlation with thiopurine related toxicity in ALL patients.
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Affiliation(s)
- Minu Singh
- Haematology-Oncology Unit, Department of Paediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Divya Bhaskar
- Haematology-Oncology Unit, Department of Paediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Prateek Bhatia
- Haematology-Oncology Unit, Department of Paediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Rozy Thakur
- Haematology-Oncology Unit, Department of Paediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Pankaj Sharma
- Haematology-Oncology Unit, Department of Paediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Deepak Bansal
- Haematology-Oncology Unit, Department of Paediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Richa Jain
- Haematology-Oncology Unit, Department of Paediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Amita Trehan
- Haematology-Oncology Unit, Department of Paediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
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Allele-specific polymerase chain reaction can determine the diplotype of NUDT15 variants in patients with childhood acute lymphoblastic Leukemia. Sci Rep 2023; 13:490. [PMID: 36627439 PMCID: PMC9832159 DOI: 10.1038/s41598-023-27720-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 01/06/2023] [Indexed: 01/12/2023] Open
Abstract
Mercaptopurine intolerance is an adverse effect of mercaptopurine administration in pediatric patients with acute lymphoblastic leukemia (ALL). NUDT15 variants have emerged as major determinants of mercaptopurine intolerance, especially in the Asian population. Two variants, c.55_56insGAGTCG in exon 1 and c.415C > T in exon 3, were commonly detected in the same allele, named NUDT15*1/*2. Although rare, compound heterozygous mutations also occur, with the two variants on different alleles (NUDT15*3/*6), which may confer tolerance to considerably lesser mercaptopurine dosage. Sanger sequencing or pyrosequencing can determine the NUDT15 variants but not the phase. Here, we designed an allele-specific PCR (AS-PCR) with locked nucleic acid-modified primers. A cohort of 63 patients harboring heterozygous c.55_56insGAGTCG and c.415C > T NUDT15 variations was selected for haplotyping using AS-PCR. Of the 63 patients, 60 harbored the NUDT15*1/*2 variant and three harbored compound heterozygous mutations, including two NUDT15*3/*6 and one NUDT15*2/*7 variants. These findings suggest that AS-PCR can determine NUDT15 diplotype and identify patients with compound heterozygous NUDT15 variants, which may enable precise genetic diagnosis of NUDT15. Nevertheless, a larger clinical trial is required to understand the clinical significance of NUDT15*3/*6 in pediatric patients with ALL because of its low incidence rate and challenges in detecting this variant.
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Tanaka Y, Urayama KY, Mori M, Arakawa Y, Hasegawa D, Noguchi Y, Yanagimachi M, Keino D, Ota S, Akahane K, Inukai T, Hangai M, Kawaguchi T, Takagi M, Koh K, Matsuda F, Manabe A. Prominence of NUDT15 genetic variation associated with 6-mercaptopurine tolerance in a genome-wide association study of Japanese children with acute lymphoblastic leukaemia. Br J Haematol 2022; 199:260-269. [PMID: 35961941 DOI: 10.1111/bjh.18405] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/30/2022] [Accepted: 08/01/2022] [Indexed: 12/01/2022]
Abstract
Inherited genetic variation is associated with 6-mercaptopurine (6-MP) dose reduction and frequent toxicities induced by 6-MP. However, the tolerable dose for 6-MP is not fully predicted by the known variation in NUDT15 and TPMT among Asian children with acute lymphoblastic leukaemia (ALL). We performed a genome-wide association study (GWAS) related to 6-MP dose among Japanese children with ALL. This GWAS comprised 224 patients previously enrolled in Tokyo Children's Cancer Study Group clinical studies with replication attempted in 55 patients. Genome-wide single nucleotide polymorphism (SNP) genotypes were evaluated for association with average 6-MP dose during the initial 168 days of maintenance therapy. Possible associations were observed across five gene-coding regions, among which only variants at 13q14.2 were significant and replicated genome-wide (rs116855232, NUDT15, β = -10.99, p = 3.7 × 10-13 ). Notable findings were observed for variants in AFF3 (rs75364948, p = 2.05 × 10-6 ) and CHST11 (rs1148407, p = 2.09 × 10-6 ), but were not replicated possibly due to small numbers. A previously reported candidate SNP in MTHFR was associated with higher average 6-MP dose (rs1801133, p = 0.045), and FOLH1 (rs12574928) was associated in an evaluation of candidate regions (padjust = 0.013). This study provides strong evidence that rs116855232 in NUDT15 is the genetic factor predominantly associated with 6-MP tolerable dose in children in Japan.
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Affiliation(s)
- Yoichi Tanaka
- Division of Medical Safety Sciences, National Institute of Health Sciences, Kanagawa, Japan
| | - Kevin Y Urayama
- Graduate School of Public Health, St. Luke's International University, Tokyo, Japan.,Department of Social Medicine, National Center for Child Health and Development, Tokyo, Japan
| | - Makiko Mori
- Department of Hematology/Oncology, Saitama Children's Medical Center, Saitama, Japan
| | - Yuki Arakawa
- Department of Hematology/Oncology, Saitama Children's Medical Center, Saitama, Japan
| | - Daisuke Hasegawa
- Department of Pediatrics, St. Luke's International Hospital, Tokyo, Japan
| | - Yasushi Noguchi
- Department of Pediatrics, Japanese Red Cross Narita Hospital, Chiba, Japan
| | - Masakatsu Yanagimachi
- Department of Hematology/Oncology, Children's Cancer Center, Kanagawa Children's Medical Center, Kanagawa, Japan.,Department of Pediatrics, Yokohama City University Hospital, Kanagawa, Japan
| | - Dai Keino
- Department of Hematology/Oncology, Children's Cancer Center, Kanagawa Children's Medical Center, Kanagawa, Japan.,Department of Pediatrics, St. Marianna University, Kanagawa, Japan
| | - Setsuo Ota
- Department of Pediatrics, Teikyo University Chiba Medical Center, Chiba, Japan
| | - Koshi Akahane
- Department of Pediatrics, University of Yamanashi, Yamanashi, Japan
| | - Takeshi Inukai
- Department of Pediatrics, University of Yamanashi, Yamanashi, Japan
| | - Mayumi Hangai
- Department of Social Medicine, National Center for Child Health and Development, Tokyo, Japan
| | | | - Masatoshi Takagi
- Department of Pediatrics, Tokyo Medical and Dental University, Tokyo, Japan
| | - Katsuyoshi Koh
- Department of Hematology/Oncology, Saitama Children's Medical Center, Saitama, Japan
| | | | - Atsushi Manabe
- Department of Pediatrics, Hokkaido University, Hokkaido, Japan
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Dumont V, Lehtonen S. PACSIN proteins in vivo: Roles in development and physiology. Acta Physiol (Oxf) 2022; 234:e13783. [PMID: 34990060 PMCID: PMC9285741 DOI: 10.1111/apha.13783] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 11/15/2021] [Accepted: 01/01/2022] [Indexed: 12/22/2022]
Abstract
Protein kinase C and casein kinase substrate in neurons (PACSINs), or syndapins (synaptic dynamin‐associated proteins), are a family of proteins involved in the regulation of cell cytoskeleton, intracellular trafficking and signalling. Over the last twenty years, PACSINs have been mostly studied in the in vitro and ex vivo settings, and only in the last decade reports on their function in vivo have emerged. We first summarize the identification, structure and cellular functions of PACSINs, and then focus on the relevance of PACSINs in vivo. During development in various model organisms, PACSINs participate in diverse processes, such as neural crest cell development, gastrulation, laterality development and neuromuscular junction formation. In mouse, PACSIN2 regulates angiogenesis during retinal development and in human, PACSIN2 associates with monosomy and embryonic implantation. In adulthood, PACSIN1 has been extensively studied in the brain and shown to regulate neuromorphogenesis, receptor trafficking and synaptic plasticity. Several genetic studies suggest a role for PACSIN1 in the development of schizophrenia, which is also supported by the phenotype of mice depleted of PACSIN1. PACSIN2 plays an essential role in the maintenance of intestinal homeostasis and participates in kidney repair processes after injury. PACSIN3 is abundant in muscle tissue and necessary for caveolar biogenesis to create membrane reservoirs, thus controlling muscle function, and has been linked to certain genetic muscular disorders. The above examples illustrate the importance of PACSINs in diverse physiological or tissue repair processes in various organs, and associations to diseases when their functions are disturbed.
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Affiliation(s)
- Vincent Dumont
- Department of Pathology and Research Program for Clinical and Molecular Metabolism Faculty of Medicine University of Helsinki Helsinki Finland
| | - Sanna Lehtonen
- Department of Pathology and Research Program for Clinical and Molecular Metabolism Faculty of Medicine University of Helsinki Helsinki Finland
- Department of Pathology University of Helsinki Helsinki Finland
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Khaeso K, Komvilaisak P, Chainansamit SO, Nakkam N, Suwannaying K, Kuwatjanakul P, Hikino K, Dornsena A, Kanjanawart S, Laoaroon N, Vannaprasaht S, Taketani T, Tassaneeyakul W. NUDT15 is a key genetic factor for prediction of hematotoxicity in pediatric patients who received a standard low dosage regimen of 6-mercaptopurine. Drug Metab Pharmacokinet 2021; 43:100436. [PMID: 35016134 DOI: 10.1016/j.dmpk.2021.100436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/21/2021] [Accepted: 11/25/2021] [Indexed: 12/25/2022]
Abstract
6-Mercaptopurine (6-MP) is commonly used for treatment of acute lymphoblastic leukemia (ALL). The incidence of hematotoxicity caused by this drug is quite high in Asians even using a standard low dosage regimen. The present study was aimed to elucidate the impact of thiopurine S-methyltransferase (TPMT), a nucleoside diphosphate-linked moiety X-type motif 15 (NUDT15), inosine triphosphatase (ITPA) and ATP Binding Cassette Subfamily C Member 4 (ABCC4) polymorphisms on hematotoxicity in pediatric patients who received a standard low starting dose of 6-MP. One hundred and sixty-nine pediatric patients were enrolled and their genotypes were determined. Patients who carried NUDT15∗3 and NUDT15∗2 genotypes were at a 10-15 fold higher risk of severe neutropenia than those of the wild-type during the early months of the maintenance phase. Risk of neutropenia was not significantly increased in patients with other NUDT15 variants as well as in patients with TPMT, ITPA or ABCC4 variants. These results suggest that NUDT15 polymorphisms particularly, NUDT15∗3 and NUDT15∗2, play major roles in 6-MP-induced severe hematotoxicity even when using a standard low dosage of 6-MP and genotyping of these variants is necessary in order to obtain precise tolerance doses and avoid severe hematotoxicity in pediatric patients.
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Affiliation(s)
- Kanyarat Khaeso
- Department of Pharmacology, Faculty of Medicine, Khon Kaen University, Thailand
| | | | | | - Nontaya Nakkam
- Department of Pharmacology, Faculty of Medicine, Khon Kaen University, Thailand
| | - Kunanya Suwannaying
- Department of Pediatrics, Faculty of Medicine, Khon Kaen University, Thailand
| | | | - Keiko Hikino
- Laboratory for Pharmacogenomics, RIKEN Center for Integrative Medical Sciences, Yokohama City, Kanagawa, Japan
| | - Areerat Dornsena
- Department of Pharmacology, Faculty of Medicine, Khon Kaen University, Thailand
| | - Sirimas Kanjanawart
- Department of Pharmacology, Faculty of Medicine, Khon Kaen University, Thailand
| | - Napat Laoaroon
- Department of Pediatrics, Faculty of Medicine, Khon Kaen University, Thailand
| | - Suda Vannaprasaht
- Department of Pharmacology, Faculty of Medicine, Khon Kaen University, Thailand
| | - Takeshi Taketani
- Department of Pediatrics, Faculty of Medicine, Shimane University, Izumo, Japan
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[Effect of genetic polymorphism of TPMT and NUDT15 on the tolerance of 6-mercaptopurine therapy in adult acute lymphoblastic leukemia]. ZHONGHUA XUE YE XUE ZA ZHI = ZHONGHUA XUEYEXUE ZAZHI 2021; 42:911-916. [PMID: 35045652 PMCID: PMC8763585 DOI: 10.3760/cma.j.issn.0253-2727.2021.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Objective: To investigate the effect of genetic polymorphisms of TPMT*2 rs1800462, TPMT*3B rs1800460, TPMT*3C rs1142345, and NUDT15 rs116855232 on the tolerance of 6-mercaptopurine (6-MP) therapy in adult acute lymphoblastic leukemia (ALL) . Methods: A total of 216 adult patients who were diagnosed with ALL and treated with cyclophosphamide, cytarabine, and 6-MP [complementary and alternative medicine (CAM) regimen] from September 2015 to December 2019 were included. Polymorphisms were detected by TaqMan SNP Genotyping Assay. Combined with clinical data, the influence of genetic polymorphism on the tolerance of 6-MP in the treatment of ALL was analyzed. Results: Among the 216 patients, 185 (85.65%) patients had B-ALL and 31 (14.35%) patients had T-ALL. 216 (100%) patients had CC genotype for both TPMT*2 rs1800462 and TPMT*3B rs1800460. The number of TT and TC genotypes for TPMT*3C rs1142345 was 209 (96.76%) and 7 (3.24%) , respectively. The allele frequency was 1.62% for TPMT*3C rs1142345. The number of CC, CT, and TT genotypes for NUDT15 rs116855232 was 166 (76.85%) , 48 (22.22%) , and 2 (0.93%) , respectively. The allele frequency was 12.04% for NUDT15 rs116855232. The TPMT*3C rs1142345 mutant group (TC+CC genotype) had less transfusion volume of packed red blood cell than the wild group (CC genotype) (P=0.036) , and the mutant group (TC+CC genotype) had a higher risk to develop hepatotoxicity (increased aspartate aminotransferase) than the wild group (CC genotype) (OR=9.559, 95% CI 1.135-80.475, P=0.038) . The durations of white blood cells (WBC) <1×10(9)/L and absolute neutrophil count (ANC) <0.5×10(9)/L in the NUDT15 rs116855232 mutation group (CT+TT genotype) were longer than that in the wild group (CC genotype) (P=0.005, P=0.007) , and the transfusion volume of apheresis-derived platelets in the mutant group (CT+TT type) was greater than that in the wild group (CC genotype) (P=0.014) . Conclusion: Genetic polymorphism of TMPT and NUDT15 has an effect on the tolerance of 6-MP in the treatment of adult ALL. Detecting genotypes of patients with ALL before treatment helps to optimize the dosage of 6-MP, which may help shorten the bone marrow suppression duration and reduce blood transfusion volume.
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Miao Q, Yan L, Zhou Y, Li Y, Zou Y, Wang L, Bai Y, Zhang J. Association of genetic variants in TPMT, ITPA, and NUDT15 with azathioprine-induced myelosuppression in southwest china patients with autoimmune hepatitis. Sci Rep 2021; 11:7984. [PMID: 33846471 PMCID: PMC8042108 DOI: 10.1038/s41598-021-87095-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 03/23/2021] [Indexed: 02/05/2023] Open
Abstract
This study aimed to investigate the influence of TPMT*3C, ITPA, NUDT15, and 6-thioguanine nucleotides (6-TGN) on azathioprine (AZA)-induced myelosuppression in Southwest China patients with autoimmune hepatitis (AIH). A total of 113 Chinese patients with AIH receiving AZA maintenance treatment were evaluated. The relevant clinical data of the patients were collected from the hospital information system. Genotyping of TPMT*3C(rs1142345), ITPA (rs1127354) and NUDT15(rs116855232) was conducted using a TaqMan double fluorescent probe. The concentration of 6-TGN was determined using UPLC-MS/MS. Among AIH patients treated with AZA, 40 (35.4%) exhibited different degrees of myelosuppression. The NUDT15 variant was associated with leukopenia (P = 8.26 × 10–7; OR = 7.5; 95% CI 3.08–18.3) and neutropenia (P = 3.54 × 10–6; OR = 8.05; 95% CI 2.96–21.9); however, no significant association with myelosuppression was observed for TPMT*3C and ITPA variants (P > 0.05). There was no significant difference in 6-TGN concentration between AIH patients with or without myelosuppression (P = 0.556), nor was there a significant difference between patients with variant alleles of TPMT*3C, ITPA, or NUDT15 and wild-type patients (P > 0.05). Interestingly, it was found that patients with a lower BMI had higher adjusted 6-TGN levels and a higher incidence of myelosuppression (P = 0.026 and 0.003). This study confirmed that NUDT15 variants are a potential independent risk predictor for AZA-induced leukopenia and neutropenia. BMI may be a crucial non-genetic factor that affects the concentration of AZA metabolites and myelosuppression. In addition, the 6-TGN concentration in red blood cells does not reflect the toxicity of AZA treatment, and new biomarkers for AZA therapeutic drug monitoring need further research.
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Affiliation(s)
- Qiang Miao
- Department of Laboratory Medicine/Research Center of Clinical Laboratory Medicine, West China Hospital of Sichuan University, No.37, Guoxue Xiang, Wuhou District, Chengdu, 610041, China
| | - Lin Yan
- Department of Laboratory Medicine/Research Center of Clinical Laboratory Medicine, West China Hospital of Sichuan University, No.37, Guoxue Xiang, Wuhou District, Chengdu, 610041, China
| | - Yanhong Zhou
- Department of Laboratory Medicine/Research Center of Clinical Laboratory Medicine, West China Hospital of Sichuan University, No.37, Guoxue Xiang, Wuhou District, Chengdu, 610041, China
| | - Yi Li
- Department of Laboratory Medicine/Research Center of Clinical Laboratory Medicine, West China Hospital of Sichuan University, No.37, Guoxue Xiang, Wuhou District, Chengdu, 610041, China
| | - Yuangao Zou
- Department of Laboratory Medicine/Research Center of Clinical Laboratory Medicine, West China Hospital of Sichuan University, No.37, Guoxue Xiang, Wuhou District, Chengdu, 610041, China
| | - Lanlan Wang
- Department of Laboratory Medicine/Research Center of Clinical Laboratory Medicine, West China Hospital of Sichuan University, No.37, Guoxue Xiang, Wuhou District, Chengdu, 610041, China
| | - Yangjuan Bai
- Department of Laboratory Medicine/Research Center of Clinical Laboratory Medicine, West China Hospital of Sichuan University, No.37, Guoxue Xiang, Wuhou District, Chengdu, 610041, China.
| | - Junlong Zhang
- Department of Laboratory Medicine/Research Center of Clinical Laboratory Medicine, West China Hospital of Sichuan University, No.37, Guoxue Xiang, Wuhou District, Chengdu, 610041, China.
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Determination of NUDT15 variants by targeted sequencing can identify compound heterozygosity in pediatric acute lymphoblastic leukemia patients. Sci Rep 2020; 10:14400. [PMID: 32873882 PMCID: PMC7463237 DOI: 10.1038/s41598-020-71468-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 08/17/2020] [Indexed: 12/14/2022] Open
Abstract
Mercaptopurine intolerance is an adverse effect of mercaptopurine administration in pediatric acute lymphoblastic leukemia. Recently, NUDT15 variants were identified as a major determinant of mercaptopurine intolerance. Two NUDT15 variants, c.36_37insGGAGTC and c.415C > T, are located on exons 1 and 3, respectively. Patients with heterozygous c.36_37insGGAGTC and c.415C > T can be either compound heterozygous with two variants on different alleles or heterozygous with both variants on the same allele. Because patients with biallelic NUDT15 variants are extremely sensitive to mercaptopurine, clinical identification of NUDT15 diplotype would be advantageous. A cohort of 37 patients with c.36_37insGGAGTC and c.415C > T NUDT15 variants were selected for haplotyping by targeted sequencing. NUDT15 complementary DNA was amplified and sequenced by 300-bp paired-end sequencing on Illumina MiSeq. Of the 37 patients carrying NUDT15 variants, 35 had heterozygous NUDT15*1/*2 variants and two had compound heterozygous NUDT15*3/*6 and NUDT15*2/*7 variants. These two patients with compound heterozygous variants could only tolerate low doses of mercaptopurine, similar to patients with homozygous NUDT15 variants. Targeted sequencing of NUDT15 cDNA can be used to determine NUDT15 diplotype and identify patients with compound heterozygous NUDT15 variants.
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