Expanding the Clinical Spectrum of LYRM7-Associated Mitochondrial Complex III Deficiency: Insights from New Cases and Literature Review

This peer-reviewed case series examines LYRM7-associated mitochondrial complex III (CIII) deficiency, a rare and typically neurodegenerative mitochondrial disorder, expanding its known phenotypic spectrum through two newly described cases and a literature review.

By
October 20, 2026
2 min

Phoenix Children's Medical Connection

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The case series describes two brothers with LYRM7-associated mitochondrial complex III deficiency and marked differences in disease course.
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One brother had relapsing ataxic episodes, longitudinally extensive transverse myelitis, and optic neuritis that initially suggested inflammatory demyelination.
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The younger brother had a more rapidly progressive course and died early.
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Both patients had cystic white matter changes and longitudinally extensive transverse myelitis on neuroimaging.
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Whole-exome sequencing and confirmatory Sanger testing identified a pathogenic LYRM7 variant, illustrating how mitochondrial disease can mimic inflammatory demyelination.

Expanding the Clinical Spectrum of LYRM7-Associated Mitochondrial Complex III Deficiency: Insights from New Cases and Literature Review

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Original Source(s)

Expanding the Clinical Spectrum of LYRM7-Associated Mitochondrial Complex III Deficiency: Insights from New Cases and Literature Review

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