A twin study of chronic fatigue

Department of Medicine, University of Washington, Seattle, WA, USA.
Psychosomatic Medicine (Impact Factor: 4.09). 01/2001; 63:936-943. DOI: 10.1097/00006842-200111000-00012
Source: PubMed

ABSTRACT OBJECTIVE: The etiology of chronic fatigue syndrome is unknown, but genetic influences may be important in its expression. Our objective was to assess the role of genetic and environmental factors in unexplained chronic fatigue. METHODS: A classic twin study was conducted using 146 female-female twin pairs, of whom at least one member reported > or =6 months of fatigue. After completing questionnaires on symptoms, zygosity, physical health, and a psychiatric interview, twins were classified using three increasingly stringent definitions: 1) chronic fatigue for > or =6 months, 2) chronic fatigue not explained by exclusionary medical conditions, and 3) idiopathic chronic fatigue not explained by medical or psychiatric exclusionary criteria of the chronic fatigue syndrome case definition. Concordance rates in monozygotic and dizygotic twins were calculated for each fatigue definition along with estimates of the relative magnitude of genetic and environmental influences on chronic fatigue. RESULTS: The concordance rate was higher in monozygotic than dizygotic twins for each definition of chronic fatigue. For idiopathic chronic fatigue, the concordance rates were 55% in monozygotic and 19% in dizygotic twins (p =.042). The estimated heritability in liability was 19% (95% confidence interval = 0-56) for chronic fatigue > or =6 months, 30% (95% confidence interval = 0-81) for chronic fatigue not explained by medical conditions, and 51% (95% confidence interval = 7-96) for idiopathic chronic fatigue. CONCLUSIONS: These results provide evidence supporting the familial aggregation of fatigue and suggest that genes may play a role in the etiology of chronic fatigue syndrome.

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    • "CFS may have a familial predisposition as relatives of patients with CFS may not necessarily meet the criteria for CFS but may be more prone to experience some of the symptoms of CFS (Walsh et al., 2001). Although twin studies allude to the existence of a genetic predisposition to CFS, this may be higher among monozygotic twins compared to dizygotic twins (Buchwald et al., 2001). Twins with CFS may share similar symptoms and experience the same level of severity in CFS related symptoms (Claypoole et al., 2007). "
    An International Perspective on the Future of Research in Chronic Fatigue Syndrome, 02/2012; , ISBN: 978-953-51-0072-0
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    • "Subjects were classified based on the 1994 Centers for Disease Control and Prevention (CDC) CFS case definition (Fukuda, et al., 1994). This cohort has been extensively evaluated in a number of studies regarding the biology of CFS (Aaron, et al., 2002; Aaron, et al., 2001; Armitage, et al., 2009; Ball, et al., 2004; Buchwald, et al., 2001; K. Claypoole, et al., 2001; K. H. Claypoole, et al., 2007; Herrell, et al., 2002; Lewis, et al., 2001; Mahurin, et al., 2004; Poole, Herrell, Ashton, Goldberg, & Buchwald, 2000; Roy-Byrne, et al., 2002; Watson, Jacobsen, Goldberg, Kapur, & Buchwald, 2004; Watson, et al., 2003), and our group has previously reported on immune parameters associated with CFS (Koelle, et al., 2002; Sabath, et al., 2002). From the original samples obtained in 2001 as described in (Koelle, et al., 2002; Sabath, et al., 2002), material was available for this study from 21 same-sex twin pairs (19 female, 2 male). "
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    ABSTRACT: A recent report suggested an association between xenotropic murine leukemia virus-related virus (XMRV) and chronic fatigue syndrome (CFS). If confirmed, this would suggest that antiretroviral therapy might benefit patients suffering from CFS. We validated a set of assays for XMRV and evaluated the prevalence of XMRV in a cohort of monozygotic twins discordant for CFS. Stored peripheral blood mononuclear cell (PBMC) samples were tested with 3 separate polymerase chain reaction (PCR) assays (one of which was nested) for XMRV DNA, and serum/plasma was tested for XMRV RNA by reverse transcription (RT)-PCR. None of the PBMC samples from the twins with CFS or their unaffected co-twins was positive for XMRV, by any of the assays. One plasma sample, from an unaffected co-twin, was reproducibly positive by RT-PCR. However, serum from the same day was negative, as was a follow-up plasma sample obtained 2 days after the positive specimen. These data do not support an association of XMRV with CFS.
    Diagnostic microbiology and infectious disease 09/2011; 71(1):66-71. DOI:10.1016/j.diagmicrobio.2011.06.003 · 2.57 Impact Factor
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    • "Familial aggregation of FM has been repeatedly demonstrated [2] [3] [4], and a twin study of CWP estimated heritability to be approximately 50% [5]. Twin studies have also reported a genetic component to CFS [6] [7] and IBS [8] [9]. Not all twin studies of IBS, however, have reported a genetic component [10] [11], and others have found that the observed genetic component is explained by a genetic influence on associated psychiatric disorder or a tendency to report multiple bodily symptoms [12] [13]. "
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    ABSTRACT: Functional somatic syndromes commonly occur together, share a genetic component and are associated with numerous somatic symptoms. This study aimed to determine if genetic variation in two neuroendocrine systems, the serotoninergic system and the hypothalamic-pituitary-adrenal (HPA) axis, was associated with the number of reported somatic symptoms. This population-based cohort study (Epidemiology of Functional Disorders) recruited participants from three primary care registers in the northwest of England. Somatic symptoms, anxiety, depression, and pain were assessed using the Somatic Symptoms Checklist, Hospital Anxiety and Depression scales, and body manikins, respectively, via a postal questionnaire. Tag Single Nucleotide Polymorphisms (SNPs) (r(2)>0.8) were selected for serotoninergic system genes (TPH2, SLC6A4 and HTR2A) and HPA axis genes (CRH, CRHR1, CRHBP, MC2R, POMC, NR3C1, and SERPINA6) and genotyped using Sequenom technology. Negative binomial regression was used to test for association between SNPs and the number of somatic symptoms. Stepwise-regression was used to identify independent effects and adjustments were made for anxiety, depression, and pain. A total of 967 subjects were successfully genotyped for 143 (87%) SNPs. Multiple SNP associations with the number of somatic symptoms were observed in HTR2A and SERPINA6 as well as two SNPs in TPH2. Stepwise regression identified two effects in HTR2A and a single effect in TPH2 which were independent of anxiety, depression, and pain. A single effect was also identified in SERPINA6 but was no longer significant when adjusted for pain. This study finds association of SNPs in HTR2A, SERPINA6, and TPH2 with somatic symptoms implicating them as potentially important in the shared genetic component to functional somatic syndromes, although replication is required.
    Journal of psychosomatic research 05/2010; 68(5):469-74. DOI:10.1016/j.jpsychores.2010.01.024 · 2.84 Impact Factor
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