Functional Testing From Skin Biopsy Improves Detection of Mitochondrial Disease

Mitochondrial diseases are rare genetic disorders that impair the body’s ability to produce energy and can affect multiple organs. They affect approximately 1 in 5,000 people, but diagnosis can remain difficult even after genetic testing. Current genetic testing identifies a definitive genetic cause in only about 50% to 65% of cases. New findings demonstrate that functional testing from a small skin biopsy can help address this diagnostic gap.

Children’s Hospital Colorado and the University of Colorado Anschutz School of Medicine evaluated advanced laboratory testing for primary mitochondrial diseases. The study examined a comprehensive set of functional diagnostic tests that measure mitochondrial performance inside cells. The approach uses fibroblasts grown from a small skin biopsy to generate diagnostic information, potentially reducing the need for more invasive procedures such as muscle or liver biopsies.

.Image: Paradigm for the diagnosis of Primary mitochondrial disorders (Johan L K Van Hove et al. EMBO Molecular Medicine, 2026. https://doi.org/10.1038/s44321-026-00497-3)

The study included samples from more than 30 medical centers across North America, Europe, Australia and New Zealand. It was conducted at the University of Colorado Anschutz campus and is described as one of the largest studies to date evaluating advanced laboratory testing for mitochondrial disease. The research assessed how effectively the functional tests identify mitochondrial disease and distinguish affected patients from those without the condition.

The findings showed that fibroblast-based testing can often provide information needed for diagnosis. The publication also represents the first comprehensive evaluation of the clinical performance of these tests, including how often they contribute to diagnosis and how accurately they identify mitochondrial disease. Nearly all of the functional tests examined are now available through the Mitochondrial Diagnostic Laboratory within the Department of Pathology and Laboratory Medicine at Children’s Hospital Colorado.

The study, “Comprehensive functional testing in fibroblasts has strong utility to diagnose mitochondrial disease,” was published in EMBO Molecular Medicine. The work involved Children’s Hospital Colorado, the University of Colorado Anschutz School of Medicine and medical centers across multiple regions. Children’s Hospital Colorado receives patient samples from medical centers throughout the United States and Canada for mitochondrial functional testing.

“Diagnosing mitochondrial disease can be incredibly challenging for patients, families and clinicians. While advances in genetic testing have transformed our ability to identify many of these conditions, a significant number of patients still do not receive clear answers. This study shows that functional testing can play a critical role in closing that gap,” said Johan Van Hove, M.D., Ph.D., clinical biochemical genetics and metabolism specialist at Children’s Colorado and professor at the University of Colorado Anschutz School of Medicine.

“For patients and families, reducing the need for invasive procedures is a meaningful advance. Being able to obtain critical diagnostic information from a simple skin biopsy has the potential to make the diagnostic process more accessible and less burdensome,” added Van Hove.

Related Links
Children’s Hospital Colorado 
University of Colorado Anschutz School of Medicine