UQCRC2-related mitochondrial complex III deficiency, about 7 patients

Area of Science:

• Biochemistry
• Genetics
• Mitochondrial Medicine

Background:

• Isolated complex III deficiency is a rare mitochondrial disorder with limited reported cases.
• UQCRC2 encodes a core subunit of complex III, crucial for the electron transport chain.
• Understanding UQCRC2 deficiency expands knowledge of mitochondrial disease genetics and pathophysiology.

Purpose of the Study:

• To describe the clinical phenotype of UQCRC2 deficiency in seven French patients.
• To highlight unique clinical features and metabolic similarities observed in UQCRC2 deficiency.
• To evaluate the therapeutic potential of glucose infusion and coenzyme Q10 supplementation.

Main Methods:

• Clinical case series of seven patients diagnosed with UQCRC2 deficiency.
• Phenotypic characterization including metabolic decompensations and treatment responses.
• Discussion of biochemical pathways and potential therapeutic interventions.

Main Results:

• Seven French patients with UQCRC2 deficiency were identified.
• Patients exhibited similarities to neoglucogenesis defects, including hypoglycemia, liver failure, and lactic acidosis.
• Rapid clinical improvement was observed following glucose fluid infusion, a notable response for mitochondrial disorders.

Conclusions:

• UQCRC2 deficiency presents a distinct phenotype within mitochondrial disorders, mimicking neoglucogenesis defects.
• Prompt glucose administration is a critical and effective intervention during metabolic decompensations.
• The role of coenzyme Q10 supplementation warrants further investigation for UQCRC2 deficiency management.