No evidence for paternal inheritance of mtDNA in patients with sporadic mtDNA mutations
Marianne Schwartz1, John Vissing
1Department of Clinical Genetics 4062, National University Hospital, Righospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark. Schwartz@rh.dk
Abstract:
With the publication of a patient with severe exercise intolerance, in whom the mutated mtDNA in muscle was shown to be paternally inherited, the strict maternal inheritance of mtDNA was challenged. Paternal mtDNA inheritance may have gone unrecognized in cases of mitochondrial disease with no clear maternal pattern of inheritance because mitochondrial haplotypes are rarely investigated in diagnostic analyses. To find further evidence for a paternal inheritance of mtDNA, we reinvestigated 12 patients with mitochondrial myopathy, in whom the pathogenic mutation was known to be sporadic. We compared the mtDNA haplotypes from the patient's muscle with that of the mtDNA haplotypes in blood from either the mother or the patient. No evidence of paternal inheritance of mtDNA was found in this small study. Although these findings indicate that the paternal inheritance of mtDNA is rare, they do not rule out that the phenomenon may occur at a rate that could still affect genetic counselling and anthropological research.
Insights
Paternal mitochondrial DNA (mtDNA) inheritance is rare, as this study found no evidence in 12 patients with mitochondrial myopathy. While not entirely ruled out, this finding impacts genetic counseling and anthropological research.
Area of Science:
- Genetics
- Molecular Biology
- Human Physiology
Background:
- Mitochondrial DNA (mtDNA) is typically maternally inherited.
- A previous case challenged this with evidence of paternal mtDNA inheritance in a patient with exercise intolerance.
- Paternal inheritance may be overlooked due to infrequent haplotype analysis in diagnostics.
Purpose of the Study:
- To investigate further evidence for paternal inheritance of mtDNA.
- To determine the frequency of paternal mtDNA inheritance in patients with mitochondrial myopathy.
Main Methods:
- Reinvestigated 12 patients diagnosed with sporadic mitochondrial myopathy.
- Compared mtDNA haplotypes from patient muscle tissue with mtDNA haplotypes from maternal blood or patient blood.
Main Results:
- No evidence of paternal mtDNA inheritance was detected in the 12 patients studied.
- The study's small sample size limits definitive conclusions about the overall rarity.
Conclusions:
- Paternal inheritance of mtDNA appears to be a rare phenomenon.
- The possibility of paternal mtDNA inheritance, though infrequent, warrants consideration in genetic counseling and anthropological studies.
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