Dataset Information

Evaluation of the X-linked modifier loci for Leber hereditary optic neuropathy with the G11778A mutation in Chinese.

ABSTRACT:

Purpose

To test the association of the X-chromosome regions (Xp21.1-q21.2 and Xq25-27.2) with Leber hereditary optic neuropathy (LHON) in Chinese patients.

Methods

One hundred and seventy-five male LHON patients with the G11778A mutation and 100 unrelated normal males participated. Twelve microsatellite markers and four single-nucleotide polymorphisms (SNPs) were genotyped for patients and controls. A chi(2) or Fisher's exact test was used to compare the frequencies of genotypes as well as haplotypes in the two groups.

Results

Significant differences between patients and controls were found in two isolated microsatellite markers (DXS6803: chi(2)=37.17, p=2.45 x 10(-5); DXS984: chi(2)=33.88, p=1.66 x 10(-6)) based on genotype frequencies. However, no significant differences for genotype and haplotype frequencies were found in the other 14 markers located in the two reported regions of Xp21.1-q21.2 and Xq25-27.2.

Conclusions

Our results provide suggestive evidence of X-linked modifiers on the expression of LHON. Further studies are needed to identify the exact nuclear genes that might affect LHON expression.

SUBMITTER: Ji Y

PROVIDER: S-EPMC2838738 | biostudies-literature | 2010 Mar

REPOSITORIES: biostudies-literature

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Publications

Evaluation of the X-linked modifier loci for Leber hereditary optic neuropathy with the G11778A mutation in Chinese.

Ji Yanli Y Jia Xiaoyun X Li Shiqiang S Xiao Xueshan X Guo Xiangming X Zhang Qingjiong Q

Molecular vision 20100311

<h4>Purpose</h4>To test the association of the X-chromosome regions (Xp21.1-q21.2 and Xq25-27.2) with Leber hereditary optic neuropathy (LHON) in Chinese patients.<h4>Methods</h4>One hundred and seventy-five male LHON patients with the G11778A mutation and 100 unrelated normal males participated. Twelve microsatellite markers and four single-nucleotide polymorphisms (SNPs) were genotyped for patients and controls. A chi(2) or Fisher's exact test was used to compare the frequencies of genotypes a ...[more]

PMID: 20300564

Similar Datasets

Project description:PurposeTo investigate the role of mitochondrial haplotypes in the development of Leber's hereditary optic neuropathy (LHON) associated with the ND4 G11778A mutation in Chinese families.DesignEight Han Chinese families with maternally transmitted LHON were studied using clinical, genetic, and molecular evaluations.ParticipantsOne hundred sixty-seven subjects from 8 Chinese families with a wide age range and severity of visual impairment.MethodsAll subjects underwent the clinical and genetic evaluation, as well as molecular analysis of mitochondrial DNA (mtDNA).Main outcome measuresThe ophthalmologic examinations included visual acuity, visual field examination, visual evoked potentials, and fundus photography. Mitochondrial DNA analysis included the polymerase chain reaction amplification of the entire mtDNA and subsequent sequence determination.ResultsEight families exhibited extremely low penetrance of visual impairment, with the average of 13%. In particular, 14 (12 males and 2 females) of 119 matrilineal relatives in these families exhibited the variable severity and age at onset in visual dysfunction. The average age of onset of vision loss was 17 years. Molecular analysis of mtDNA identified the homoplasimic ND4 G11778A mutation and distinct sets of variants belonging to the Asian haplogroups M8a2, D4g2, B4a1c, B5b, N9a1, D4b2b, C, and M7b1. However, there was an absence of secondary LHON-associated mtDNA mutations in these 8 Chinese families.ConclusionsThe extremely low penetrance of vision loss in these 8 Chinese pedigrees strongly indicates that the G11778A mutation was itself insufficient to produce a clinical phenotype. The absence of secondary LHON mtDNA mutations suggest that these mtDNA haplogroup-specific variants may not play an important role in the phenotypic expression of the G11778A mutation in those Chinese families with very low penentrace of vision loss. However, nuclear backgrounds and environmental factors seem to be modifying factors for the phenotypic manifestation of the G11778A mutation in these Chinese families.

Project description:IMPORTANCE Establishing the natural history of G11778A Leber hereditary optic neuropathy (LHON) is important to determine the optimal end points to assess the safety and efficacy of a planned gene therapy trial. OBJECTIVE To use the results of the present natural history study of patients with G11778A LHON to plan a gene therapy clinical trial that will use allotopic expression by delivering a normal nuclear-encoded ND4 gene into the nuclei of retinal ganglion cells via an adeno-associated virus vector injected into the vitreous. DESIGN, SETTING, AND PARTICIPANTS A prospective observational study initiated in 2008 was conducted in primary and referral institutional practice settings. Participants included 44 individuals with G11778A LHON, recruited between September 2008 and March 2012, who were evaluated every 6 months and returned for 1 or more follow-up visits (6-36 months) as of August 2012. EXPOSURES Complete neuro-ophthalmic examination and main measures. MAIN OUTCOMES AND MEASURES Visual acuity, automated visual field testing, pattern electroretinogram, and spectral-domain optical coherence tomography. RESULTS Clinical measures were stable during the follow-up period, and visual acuity was as good as or better than the other visual factors used for monitoring patients. Based on a criterion of 15 or more letters from the Early Treatment Diabetic Retinopathy Study chart, 13 eyes of 8 patients (18%) improved, but 24 months after the onset of symptoms, any further improvements were to no better than 20/100. Acuity recovery occurred in some patients despite continued marked retinal nerve fiber layer thinning indistinguishable from that in patients who did not recover visual acuity. CONCLUSIONS AND RELEVANCE Spontaneous improvement of visual acuity in patients with G11778A LHON is not common and is partial and limited when it occurs, so improvements in vision with adeno-associated virus-mediated gene therapy of a synthetic wild-type ND4 subunit gene should be possible to detect with a reasonable sample size. Visual acuity appears to be the most suitable primary end point for the planned clinical trial.

Project description:BackgroundLeber hereditary optic neuropathy (LHON) is the most common mitochondrial disorder, frequently resulting in acute or subacute severe bilateral central vision loss. Vitamin B12 deficiency is also a known cause of optic neuropathy through mitochondrial dysfunction. Here we evaluated the prevalence and clinical significance of vitamin B12 deficiency in a large cohort of LHON patients and asymptomatic mutation carriers from a tertiary referral center.MethodsFrom the Munich LHON prospective cohort study, participants included all LHON patients and asymptomatic LHON mutation carriers, who were recruited between February 2014 and March 2020 and consented to participate. Neurological, general, and ophthalmological examinations were regularly performed, as were laboratory tests. Vitamin B12 deficiency was diagnosed if serum vitamin B12 was below 201 pg/mL, or if 201-339 pg/mL plus low serum holotranscobalamin or elevated serum methylmalonic acid or elevated total plasma homocysteine.ResultsWe analyzed 244 subjects, including 147 symptomatic LHON patients (74% males) and 97 asymptomatic mutation carriers (31% males). Median age at study baseline was 34 years (range 5-82 years). The prevalence of vitamin B12 deficiency was higher for LHON mutation carriers than for the general population in all age categories. This was statistically significant for the LHON mutation carriers under 65 years (21% vs. 5-7%, p = 0.002). While vitamin B12 deficiency prevalence was not statistically different between LHON patients and asymptomatic mutation carriers, its clinical correlates, e.g., macrocytosis and polyneuropathy, were more frequent in the subgroup of LHON patients. Excessive alcohol consumption was a significant predictor of vitamin B12 deficiency (p < 0.05).ConclusionsThe high prevalence of vitamin B12 deficiency in LHON mutation carriers, both asymptomatic mutation carriers and LHON patients, highlights the need for regular vitamin B12 screening in this population, in order to ensure early treatment, aiming for better outcomes. Our study is not conclusive regarding vitamin B12 deficiency as determinant for disease conversion in LHON, and further research is warranted to disentangle the role of vitamin B12 in the pathophysiology and prognosis of LHON.

Dataset Information

Evaluation of the X-linked modifier loci for Leber hereditary optic neuropathy with the G11778A mutation in Chinese.

Purpose

Methods

Results

Conclusions

Publications

Evaluation of the X-linked modifier loci for Leber hereditary optic neuropathy with the G11778A mutation in Chinese.

Similar Datasets

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