Multi-system mitochondrial disorder with recurrent steroid-responsive eosinophilia

Area of Science:

• Mitochondrial biology
• Hematology
• Immunology

Background:

• Mitochondrial disorders typically present with neurological and muscular symptoms.
• Hematological abnormalities like anemia are known complications of mitochondrial disorders.
• Recurrent hypereosinophilia has not been previously linked to mitochondrial dysfunction.

Observation:

• A 65-year-old female presented with symptoms suggestive of Churg–Strauss syndrome, including asthma, bronchitis, and recurrent hypereosinophilia.
• Biopsies excluded vasculitis, but corticosteroids effectively managed her hypereosinophilia.
• A mitochondrial disorder was diagnosed based on clinical presentation and muscle biopsy findings.

Findings:

• Hypereosinophilia was identified as a potential manifestation of a mitochondrial disorder.
• The patient's presentation mimicked Churg–Strauss syndrome due to marked eosinophilia.
• Steroid therapy provided episodic relief for hypereosinophilia but did not address other mitochondrial disease features.

Implications:

• This case expands the known clinical spectrum of mitochondrial disorders.
• It highlights the importance of considering mitochondrial disease in patients with unexplained hypereosinophilia.
• Further research is needed to understand the mechanisms linking mitochondrial dysfunction and eosinophilia.