Dataset Information

Heteroplasmy and Copy Number in the Common m.3243A>G Mutation-A Post-Mortem Genotype-Phenotype Analysis.

ABSTRACT: Different mitochondrial DNA (mtDNA) mutations have been identified to cause mitochondrial encephalopathy, lactate acidosis and stroke-like episodes (MELAS). The underlying genetic cause leading to an enormous clinical heterogeneity associated with m.3243A>G-related mitochondrial diseases is still poorly understood. Genotype-phenotype correlation (heteroplasmy levels and clinical symptoms) was analysed in 16 patients (15 literature cases and one unreported case) harbouring the m.3243A>G mutation. mtDNA copy numbers were correlated to heteroplasmy levels in 30 different post-mortem tissue samples, including 14 brain samples of a 46-year-old female. In the central nervous system, higher levels of heteroplasmy correlated significantly with lower mtDNA copy numbers. Skeletal muscle levels of heteroplasmy correlated significantly with kidney and liver. There was no significant difference of heteroplasmy levels between clinically affected and unaffected patients. In the patient presented, we found >75% heteroplasmy levels in all central nervous system samples, without harbouring a MELAS phenotype. This underlines previous suggestions, that really high levels in tissues do not automatically lead to a specific phenotype. Missing significant differences of heteroplasmy levels between clinically affected and unaffected patients underline recent suggestions that there are additional factors such as mtDNA copy number and nuclear factors that may also influence disease severity.

SUBMITTER: Scholle LM

PROVIDER: S-EPMC7073558 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature

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Heteroplasmy and Copy Number in the Common m.3243A>G Mutation-A Post-Mortem Genotype-Phenotype Analysis.

Scholle Leila Motlagh LM Zierz Stephan S Mawrin Christian C Wickenhauser Claudia C Urban Diana Lehmann DL

Genes 20200218 2

Different mitochondrial DNA (mtDNA) mutations have been identified to cause mitochondrial encephalopathy, lactate acidosis and stroke-like episodes (MELAS). The underlying genetic cause leading to an enormous clinical heterogeneity associated with m.3243A>G-related mitochondrial diseases is still poorly understood. Genotype-phenotype correlation (heteroplasmy levels and clinical symptoms) was analysed in 16 patients (15 literature cases and one unreported case) harbouring the m.3243A>G mutation. ...[more]

PMID: 32085658

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Project description:Background Xp22.31 deletion and duplication have been described in various studies, but different laboratories interpret pathogenicity differently. Objectives Our study aimed to refine the genotype–phenotype associations between Xp22.31 copy number variants in fetuses, with the aim of providing data support to genetic counseling. Methods We retrospectively analyzed karyotyping and single nucleotide polymorphism array results from 87 fetuses and their family members. Phenotypic data were obtained through follow-up visits. Results The percentage of fetuses carrying the Xp22.31 deletions (9 females, 12 males) was 24.1% (n = 21), while duplications (38 females, 28 males) accounted for 75.9% (n = 66). Here, we noted that the typical region (from 6.4 to 8.1 Mb, hg19) was detected in the highest ratio, either in the fetuses with deletions (76.2%, 16 of 21) or duplications (69.7%, 46 of 66). In female deletion carriers, termination of pregnancy was chosen for two fetuses, and the remaining seven were born without distinct phenotypic abnormalities. In male deletion carriers, termination of pregnancy was chosen for four fetuses, and the remaining eight of them displayed ichthyosis without neurodevelopmental anomalies. In two of these cases, the chromosomal imbalance was inherited from the maternal grandfathers, who also only had ichthyosis phenotypes. Among the 66 duplication carriers, two cases were lost at follow-up, and pregnancy was terminated for eight cases. There were no other clinical findings in the rest of the 56 fetuses, including two with Xp22.31 tetrasomy, for either male or female carriers. Conclusion Our observations provide support for genetic counseling in male and female carriers of Xp22.31 copy number variants. Most of them are asymptomatic in male deletion carriers, except for skin findings. Our study is consistent with the view that the Xp22.31 duplication may be a benign variant in both sexes. Supplementary Information The online version contains supplementary material available at 10.1186/s12920-023-01493-z.

Dataset Information

Heteroplasmy and Copy Number in the Common m.3243A>G Mutation-A Post-Mortem Genotype-Phenotype Analysis.

Publications

Heteroplasmy and Copy Number in the Common m.3243A>G Mutation-A Post-Mortem Genotype-Phenotype Analysis.

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