Sequence Variations in Subjects with Self-Reported Multiple Chemical Sensitivity (sMCS): A Case-Control Study

Abstract

Polymorphisms in several genes contribute to interindividual differences in the metabolism of xenobiotics, and may lead to toxicity and disease. The balance between activation and/or detoxification processes may influence an individual's susceptibility to disease. One postulated mechanism underlying multiple chemical sensitivity (MCS) is based on increased metabolism of xenobiotics. The aim of the present study was to determine such polymorphisms in cases with self-reported MCS (sMCS) and controls. sMCS cases (14 men, 45 women, mean age: 48 yr) and controls (14 men, 26 women, mean age: 44 yr) of the same anthroposphere were characterized using the MCS-questionnaire from Huppe and coworkers (2000) and a standardized questionnaire for living conditions and living factors. Allelic frequencies of genomic variations for 5HTT, NAT1, NAT2, PON1, PON2, and SOD2 were determined. The MCS questionnaire from Huppe et al. (2000) differentiated between cases and controls with 87.5% sensitivity and 90% specificity. Compared to controls the sMCS cases had lower exposures, especially to odorous factors, and worse social conditions. No significant differences of the allelic distribution of genetic polymorphisms in the genes for 5HTT, NAT1, NAT2, PON1, PON2, and SOD2 were found between cases and controls. The results are in contrast to the study of McKeown-Eyssen and coworkers (2004) but in accordance with the German MCS multicenter study. Although the MCS questionnaire from Huppe et al. (2000) allowed us to differentiate sMCS cases and controls, it was not strong enough for a discrimination based on sequence variations in genes for enzymes involved in xenobiotic metabolism. Therefore, further research needs to focus on a unique phenomenological characterization of MCS.

Factors in genetic susceptibility in a chemical sensitive population using QEESI

“…This trend in the MCS case-control design was reversed in the general population samples, perhaps reflecting that the PON1 polymorphism played a minor or no role in the development of MCS in our population. In support of our study, Wiesmuller et al [24] failed to detect an association between PON1 polymorphism and self-reported MCS in a population sample.…”

“…Several reports suggest that MCS patients who are aware of their chemical intolerance avoid exogenous chemicals such as those from smoking [23,24]. Tobacco smoke contains many kinds of chemicals, including formaldehyde and acetaldehyde [25].…”

The Search for Reliable Biomarkers of Disease in Multiple Chemical Sensitivity and Other Environmental Intolerances

“…It must be noted though, that Hg concentration in body tissues was proven to be independent of urinary, blood, saliva and hair concentrations [66]. Mercury disposition occurs in fact mainly through stools, in a ratio of 12 to 1 to urine excretion, this latter probably reflecting only kidney, and not total-body burden [67,68]. In support, urine levels of Hg below 5 μg/L (the No Observed Adverse Effect Level—NOAEL—for mercury) have been reported in cases of occupational intoxication [69].…”

The feasibility of aromatherapy massage to reduce symptoms of Idiopathic Environmental Intolerance: A pilot study

“…There are several studies underway to determine the aetiological source of IEI. Genetic polymorphisms in drug-metabolising enzymes have previously been examined; 12,13 however, genetic involvement in IEI remains unclear.…”

“…Experimental exposures to various chemicals, [12][13][14][15] as well as studies of groups at high risk for chemical exposures, 16 have also failed to identify any differences between IEI patients and control subjects. Thus, the hypothesis that frequent chemical exposure causes an increased risk for developing IEI has not yet been confirmed.…”