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Human chitotriosidase polymorphism is associated with human longevity in Mediterranean nonagenarians and centenarians

Lucia Malaguarnera1, Luca Nnawuihe Ohazuruike, Christina Tsianaka

  • 1Department of Biomedical Science, University of Catania, Via Androne 83, Catania, Italy. lucmal@mbox.unict.it

Journal of Human Genetics
|November 3, 2009
PubMed

Insights

The human chitotriosidase (CHIT-1) gene

Area of Science:

  • Genetics
  • Enzymology
  • Gerontology

Background:

  • Human phagocyte-specific chitotriosidase (CHIT-1) is a chitinolytic enzyme linked to macrophage activation and diseases like atherosclerosis, cardiovascular disease, and dementia.
  • A 24-bp duplication in the CHIT-1 gene correlates with reduced enzymatic activity.
  • The role of CHIT-1 in human longevity remains largely unexplored.

Purpose of the Study:

  • To investigate whether the CHIT-1 gene is a potential genetic factor contributing to human longevity.
  • To compare the CHIT-1 gene polymorphism genotype distribution in elderly Mediterranean populations with younger control groups.

Main Methods:

  • Genotyping of the CHIT-1 24-bp duplication polymorphism was performed in three Mediterranean populations (Italian, Greek, Tunisian) aged over 90 years.
  • Control groups of 60-70-year-old subjects were genotyped for comparison.
  • Enzymatic activity was measured in heterozygous individuals.

Main Results:

  • Heterozygote frequency for the CHIT-1 24-bp duplication was significantly higher in oldest-old subjects (nonagenarians and centenarians) compared to control groups.
  • No oldest-old subjects were homozygous for CHIT-1 deficiency.
  • Mean CHIT-1 enzymatic activity was lower in heterozygous oldest-old individuals than in controls.

Conclusions:

  • Heterozygosity for the 24-bp duplication in the CHIT-1 gene may confer a protective effect on human longevity.
  • This genetic variation could play a role in promoting exceptional lifespan in Mediterranean populations.

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