title: hTERT genetic variation in depression.
abstract: BACKGROUND
  Telomeres are protective DNA-protein complexes forming the chromosome ends. TL differs between tissues. Shorter telomere length (TL) in blood leukocytes (LTL) has been associated with major depression, and with previous exposure to childhood adversity. TL studies on non-invasively sampled salivary DNA are less common. Telomerase, with its catalytic subunit hTERT, counteracts telomere shortening. Reduced telomerase activity associates with depression-like behavior in mice. Recently, the minor allele of the hTERT polymorphism rs2736100 was associated with shorter LTL among primarily healthy individuals. We hypothesized that (i) TL in saliva DNA is shortened in adults with a history of depression, and that (ii) rs2736100 is implicated in depression and depressive episodes in bipolar disorder type 1 (BD1).
  
  
  METHODS
  Individuals with a history of depression and those without (controls) were identified using self-reported questionnaires from a well-characterized population-based cohort. Clinical BD1 patients were diagnosed by specialized psychiatrists. Saliva TL was measured in age-matched depressed individuals and controls (n=662) using qRT-PCR. rs2736100 was genotyped in 436 depressed individuals, 1590 controls, and 368 BD1 patients.
  
  
  RESULTS
  Saliva TL was shorter in depressed individuals compared to controls. The rs2736100 minor allele was associated with depression among those without experience of childhood adversity, and with number of depressive episodes in BD1 patients responding well to lithium.
  
  
  CONCLUSIONS
  Psychopathological symptoms were recorded at two time points only, 3 and 6 years prior to DNA sampling.
  
  
  CONCLUSIONS
  This is the first report on hTERT genetic variation in mood disorder. It proposes that genetic variation in hTERT may influence the susceptibility to depression.
authors.affiliation: Department of Molecular Medicine and Surgery, Neurogenetics Unit, Karolinska Institutet, Stockholm, Sweden; Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Ya Bin
authors.initials: YB
authors.lastname: Wei
authors.affiliation: Department of Clinical Neuroscience, Centre for Psychiatric Research and Education, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Lina
authors.initials: L
authors.lastname: Martinsson
authors.affiliation: Department of Molecular Medicine and Surgery, Neurogenetics Unit, Karolinska Institutet, Stockholm, Sweden; School of Nursing, Shandong University, Jinan, China.
authors.forename: Jia Jia
authors.initials: JJ
authors.lastname: Liu
authors.affiliation: Department of Public Health Science, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Forsell
authors.affiliation: Department of Molecular Medicine and Surgery, Neurogenetics Unit, Karolinska Institutet, Stockholm, Sweden; Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Schalling
authors.affiliation: Department of Molecular Medicine and Surgery, Neurogenetics Unit, Karolinska Institutet, Stockholm, Sweden; Department of Clinical Neuroscience, Centre for Psychiatric Research and Education, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Lena
authors.initials: L
authors.lastname: Backlund
authors.affiliation: Department of Molecular Medicine and Surgery, Neurogenetics Unit, Karolinska Institutet, Stockholm, Sweden; Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden. Electronic address: catharina.lavebratt@ki.se.
authors.forename: Catharina
authors.initials: C
authors.lastname: Lavebratt
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D001714:Bipolar Disorder / Q000235:genetics; D004247:DNA / Q000235:genetics; D003863:Depression / Q000235:genetics*; D003865:Major Depressive Disorder / Q000235:genetics; D005260:Female; D005838:Genotype; D006801:Humans; D007962:Leukocytes / Q000378:metabolism; D008297:Male; D051379:Mice; D011110:Polymorphism, Genetic; D011795:Surveys and Questionnaires; D019098:Telomerase / Q000235:genetics* / Q000378:metabolism; D059506:Telomere Shortening / Q000235:genetics*
chemical_list: D004247:DNA; C509186:TERT protein, human; D019098:Telomerase
keywords: Bipolar disorder; Depressive episode; Saliva; Single nucleotide polymorphism; Telomerase; Telomere