Presentation: Heritability in Fibromyalgia (2007)

1521 Heritability in Fibromyalgia

INTRODUCTION: The Fibromyalgia Syndrome (FMS) often occurs in families, and genetic susceptibility is possibly an important factor in etiology. We analyzed the responses to questions from the Fibromyalgia Impact Questionnaire(FIQ) in 140 monozygotic and 107 dizygotic twin pairs.
METHODS: Using the University of Minnesota’s Twin Registry, a survey based on the Fibromyalgia Impact Questionnaire was distributed to twin pairs. Responses were tabulated and analyzed by tetrachoric correlations using TCORR
RESULTS: There were no major differences between the monozygotic and dizygotic twin pairs in response to statements such as “I ache all over” and a visual analog scale for pain. However, there was a trend toward more fatigue in both of the monozygotic twins compared with the dizygotic twin pairs.
PrevalenceSymptom Concordance in Twin Pairs
MZ (N,
%)
DZ (N, %)MZ (N, %)DZ (N, %)
ACHEALL Answer to: I ache all over79/280 (28.2)47/214 (22.0)15/140 (10.7)7/107 (6.5)
PAIN40 FIQ Pain Indicator (>40)104/262 (39.7)78/190 (41.1)23/131 (17.6)17/95 (17.9)
TIRED50 FIQ Tired Indicator (>50)119/278 (42.8)89/204 (43.6)35/139 (25.2)19/102 (18.6)
TOOTIRED Answer to ‘Do you feel too tired during the day to do what you want to do?’66/274 (24.1)51/206 (24.8)9/137 (6.6)9/103 (8.7)
PASTMON Answer to ‘During the past month have you had any ache or pain that lasted for one day or longer?224/278 (80.6)164/208 (78.8)93/139 (66.9)67/104 (64.4)

Pair Correlations
(tetrachoric)a
Proportions of Variance
(%)b
Q ItemrMZrDZa2c2e2
ACHEALL.24242.18603.11.13.76
PAIN40.12081.10860.02.10.88
TIRED50.46421-.00758.940c.54
TOOTIRED.11723.270210c.42.88
PASTMON.26167.321910c.38.74

a Tetrachoric correlations computed using TCORR (Uebersax J, April 14, 2000; accessed December 27, 2006) (Ref: Brown MB. Algorithm AS 116: the tetrachoric correlation and its standard error. Applied Statistics 1977; 26:343-51).
CONCLUSION: There were no major differences in the FIQ responses between monozygotic and dizygotic twin pairs. There appeared to be a trend among the monozygotic twins toward similar levels of fatigue.

 R.S. Katz, None.