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DNMT3A and TET2 dominate clonal hematopoiesis and demonstrate benign phenotypes and different genetic predispositions

Manuel Buscarlet, Sylvie Provost, Yassamin Feroz Zada, Amina Barhdadi, Vincent Bourgoin, Guylaine Lépine, Luigina Mollica, Natasha Szuber, Marie-Pierre Dubé and Lambert Busque

Key Points

  • Somatic mutations driving clonal hematopoiesis occur mainly in DNMT3A and TET2 and have no significant impact on hematological phenotypes.

  • There is a familial predisposition to acquire TET2 mutation.

Publisher's Note: There is an Inside Blood Commentary on this article in this issue.

Abstract

Age-associated clonal hematopoiesis caused by acquired mutations in myeloid cancer–associated genes is highly prevalent in the normal population. Its etiology, biological impact on hematopoiesis, and oncogenic risk is poorly defined at this time. To gain insight into this phenomenon, we analyzed a cohort of 2530 related and unrelated hematologically normal individuals (ages 55 to 101 years). We used a sensitive gene-targeted deep sequencing approach to gain precision on the exact prevalence of driver mutations and the proportions of affected genes. Mutational status was correlated with biological parameters. We report a higher overall prevalence of driver mutations (13.7%), which occurred mostly (93%) in DNMT3A or TET2 and were highly age-correlated. Mutation in these 2 genes had some distinctive effects on end points. TET2 mutations were more age-dependent, associated with a modest neutropenic effect (9%, P = .012), demonstrated familial aggregation, and associated with chronic obstructive pulmonary disease. Mutations in DNMT3A had no impact on blood counts or indices. Mutational burden of both genes correlated with X-inactivation skewing but no significant association with age-adjusted telomere length reduction was documented. The discordance between the high prevalence of mutations in these 2 genes and their limited biological impact raise the question of the potential role of dysregulated epigenetic modifiers in normal aging hematopoiesis, which may include support to failing hematopoiesis.

  • Submitted March 31, 2017.
  • Accepted June 21, 2017.
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