K Tsao1, P A Aitken, D R Johns. 1. Department of Ophthalmology, University of South Carolina School of Medicine, USA.
Abstract
BACKGROUND/AIMS: Leber's hereditary optic neuropathy (LHON) is a mitochondrial DNA mediated disease which causes severe visual deficits. Although expressivity of the disease is 100%, penetrance is variable, and environmental factors may influence risk of becoming symptomatic. The causative relation between cigarette smoking and disease penetrance was examined. METHODS: The incidence of smoking in 65 age matched family members of one LHON pedigree was retrospectively obtained. Smoking in groups which expressed disease was compared with those which did not. Male subgroups were analysed separately in addition to combined sex groups. RESULTS: The association between smoking and disease penetrance was significant in all subgroups (p values from p=0.0009 to p=0.0001, 95% confidence intervals). Disease penetrance was higher in males than females. The association was weaker in the male group than combined sex groups (p values from p=0.0146 to p=0.0008, 95% confidence intervals), probably because of elimination of female asymptomatic non-smokers in the comparison groups. The association was strengthened in older age groups and in groups which smoked more heavily. CONCLUSIONS: Smoking is significantly associated with disease penetrance in this LHON pedigree. Degree of smoking and number of years smoked correlate with increased risk of developing symptoms.
BACKGROUND/AIMS: Leber's hereditary optic neuropathy (LHON) is a mitochondrial DNA mediated disease which causes severe visual deficits. Although expressivity of the disease is 100%, penetrance is variable, and environmental factors may influence risk of becoming symptomatic. The causative relation between cigarette smoking and disease penetrance was examined. METHODS: The incidence of smoking in 65 age matched family members of one LHON pedigree was retrospectively obtained. Smoking in groups which expressed disease was compared with those which did not. Male subgroups were analysed separately in addition to combined sex groups. RESULTS: The association between smoking and disease penetrance was significant in all subgroups (p values from p=0.0009 to p=0.0001, 95% confidence intervals). Disease penetrance was higher in males than females. The association was weaker in the male group than combined sex groups (p values from p=0.0146 to p=0.0008, 95% confidence intervals), probably because of elimination of female asymptomatic non-smokers in the comparison groups. The association was strengthened in older age groups and in groups which smoked more heavily. CONCLUSIONS: Smoking is significantly associated with disease penetrance in this LHON pedigree. Degree of smoking and number of years smoked correlate with increased risk of developing symptoms.
Authors: Anna Ghelli; Anna Maria Porcelli; Claudia Zanna; Sara Vidoni; Stefano Mattioli; Anna Barbieri; Luisa Iommarini; Maria Pala; Alessandro Achilli; Antonio Torroni; Michela Rugolo; Valerio Carelli Journal: PLoS One Date: 2009-11-19 Impact factor: 3.240
Authors: Matthew Anthony Kirkman; Patrick Yu-Wai-Man; Alex Korsten; Miriam Leonhardt; Konstantin Dimitriadis; Ireneaus F De Coo; Thomas Klopstock; Patrick Francis Chinnery Journal: Brain Date: 2009-06-12 Impact factor: 13.501