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A twin concordance study of trichotillomania.

Abstract

Trichotillomania (TTM) is a disorder with putative genetic underpinnings. Family studies report higher than expected rates of TTM among relatives of affected individuals, but no twin concordance studies have been completed to estimate heritability rates. Same-sex twin pairs with hair pulling in at least one co-twin were included. Subjects were recruited following phone screens and questionnaire completion for zygosity and hair pulling variables. Three sets of criteria were used to define hair pulling and TTM. Two other sets of criteria were widened to include skin picking and bothersome hair manipulation. Fisher exact tests assessed pairwise concordance rates for monozygotic and dizygotic twin pairs and heritability estimates were calculated where significant differences existed. Among 34 identified twin pairs, 24 were monozygotic (MZ) and 10 were dizygotic (DZ). Respective concordance rates for MZ and DZ twin pairs were significantly different at 38.1% and 0% for DSM-IV TTM criteria, 39.1% and 0% using modified DSM criteria, and 58.3% and 20% for noticeable non-cosmetic hair pulling (heritability estimates 76.2%). MZ and DZ concordance rates were not significantly different when broadening hair pulling criteria to include skin picking or when including bothersome hair manipulation. Concordance rates from this study suggest that genetic factors play a significant role in the etiology of TTM. Given the reported discordance rates among the MZ twins, further research is required to fully understand contributory non-genetic factors.

Authors+Show Affiliations

Health Partners, St. Paul, Minneapolis, USA.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Twin Study

Language

eng

PubMed ID

19199280

Citation

Novak, Carol E., et al. "A Twin Concordance Study of Trichotillomania." American Journal of Medical Genetics. Part B, Neuropsychiatric Genetics : the Official Publication of the International Society of Psychiatric Genetics, vol. 150B, no. 7, 2009, pp. 944-9.
Novak CE, Keuthen NJ, Stewart SE, et al. A twin concordance study of trichotillomania. Am J Med Genet B Neuropsychiatr Genet. 2009;150B(7):944-9.
Novak, C. E., Keuthen, N. J., Stewart, S. E., & Pauls, D. L. (2009). A twin concordance study of trichotillomania. American Journal of Medical Genetics. Part B, Neuropsychiatric Genetics : the Official Publication of the International Society of Psychiatric Genetics, 150B(7), pp. 944-9. doi:10.1002/ajmg.b.30922.
Novak CE, et al. A Twin Concordance Study of Trichotillomania. Am J Med Genet B Neuropsychiatr Genet. 2009 Oct 5;150B(7):944-9. PubMed PMID: 19199280.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A twin concordance study of trichotillomania. AU - Novak,Carol E, AU - Keuthen,Nancy J, AU - Stewart,S Evelyn, AU - Pauls,David L, PY - 2009/2/10/entrez PY - 2009/2/10/pubmed PY - 2009/12/29/medline SP - 944 EP - 9 JF - American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics JO - Am. J. Med. Genet. B Neuropsychiatr. Genet. VL - 150B IS - 7 N2 - Trichotillomania (TTM) is a disorder with putative genetic underpinnings. Family studies report higher than expected rates of TTM among relatives of affected individuals, but no twin concordance studies have been completed to estimate heritability rates. Same-sex twin pairs with hair pulling in at least one co-twin were included. Subjects were recruited following phone screens and questionnaire completion for zygosity and hair pulling variables. Three sets of criteria were used to define hair pulling and TTM. Two other sets of criteria were widened to include skin picking and bothersome hair manipulation. Fisher exact tests assessed pairwise concordance rates for monozygotic and dizygotic twin pairs and heritability estimates were calculated where significant differences existed. Among 34 identified twin pairs, 24 were monozygotic (MZ) and 10 were dizygotic (DZ). Respective concordance rates for MZ and DZ twin pairs were significantly different at 38.1% and 0% for DSM-IV TTM criteria, 39.1% and 0% using modified DSM criteria, and 58.3% and 20% for noticeable non-cosmetic hair pulling (heritability estimates 76.2%). MZ and DZ concordance rates were not significantly different when broadening hair pulling criteria to include skin picking or when including bothersome hair manipulation. Concordance rates from this study suggest that genetic factors play a significant role in the etiology of TTM. Given the reported discordance rates among the MZ twins, further research is required to fully understand contributory non-genetic factors. SN - 1552-485X UR - https://www.unboundmedicine.com/medline/citation/19199280/A_twin_concordance_study_of_trichotillomania_ L2 - https://doi.org/10.1002/ajmg.b.30922 DB - PRIME DP - Unbound Medicine ER -