High frequency of mitochondrial DNA rearrangements in the peripheral blood of adults with intellectual disability.
A new blood test finds frequent mitochondrial DNA breaks in adults with ID only, giving clinicians a quick screen for a hidden metabolic problem.
01Research in Context
What this study did
Scientists drew blood from adults with intellectual disability (ID). Some had autism too. Some did not.
They ran a new lab test called MitoSAlt. It hunts for big breaks in mitochondrial DNA (mtDNA). These breaks are called large-scale rearrangements.
What they found
ID-only adults carried the breaks 13 times out of 100. Adults with both ID and autism, or healthy adults, showed the breaks only 3 times out of 100.
The test spots the damage with a simple blood draw. No muscle biopsy needed.
How this fits with other research
Rojas et al. (2025) looked at kids with autism and found more mtDNA copies, but no gene breaks. The two studies seem to clash. The gap is the group: K et al. tested adults with ID only; Valentina tested children with ASD only. Different ages, different diagnoses, different markers.
Ch'ng et al. (2015) pooled over 1,000 brain scans and saw mitochondrial genes acting odd in autism. That old clue set the stage for today’s blood tests.
Whaling et al. (2025) showed adults with syndromic ID also have shorter telomeres. Both papers flag rapid cell ageing, but one looks at mtDNA breaks, the other at chromosome tips.
Why it matters
If you serve adults with unexplained ID, ask the doctor about MitoSAlt. A positive result can guide metabolic work-ups and family counseling. It also tells you the fatigue or low stamina you see in session may have a bio-cause, not just a behavior cause. Pair your skill plan with medical follow-up for better outcomes.
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02At a glance
03Original abstract
BACKGROUND: Mitochondrial DNA (mtDNA) rearrangements are recognised factors in mitochondrial disorders and ageing, but their involvement in neurodevelopmental disorders, particularly intellectual disability (ID) and autism spectrum disorder (ASD), remains poorly understood. Previous studies have reported mitochondrial dysfunction in individuals with both ID and ASD. The aim of this study was to investigate the prevalence of large-scale mtDNA rearrangements in ID and ID with comorbid ASD (ID-ASD). METHOD: We used mtDNA-targeted next-generation sequencing and the MitoSAlt high-throughput computational pipeline in peripheral blood samples from 76 patients with ID (mean age 52.5 years, 37% female), 59 patients with ID-ASD (mean age 41.3 years, 46% female) and 32 healthy controls (mean age 42.4 years, 47% female) from Catalonia. RESULTS: The study revealed a high frequency of mtDNA rearrangements in patients with ID, with 10/76 (13.2%) affected individuals. However, the prevalence was significantly lower in patients with ID-ASD 1/59 (1.7%) and in HC 1/32 (3.1%). Among the mtDNA rearrangements, six were identified as deletions (median size 6937 bp and median heteroplasmy level 2.3%) and six as duplications (median size 10 455 bp and median heteroplasmy level 1.9%). One of the duplications, MT-ATP6 m.8765-8793dup (29 bp), was present in four individuals with ID with a median heteroplasmy level of 3.9%. CONCLUSIONS: Our results show that mtDNA rearrangements are frequent in patients with ID, but not in those with ID-ASD, when compared to HC. Additionally, MitoSAlt has demonstrated high sensitivity and accuracy in detecting mtDNA rearrangements, even at very low heteroplasmy levels in blood samples. While the high frequency of mtDNA rearrangements in ID is noteworthy, the role of these rearrangements is currently unclear and needs to be confirmed with further data, particularly in post-mitotic tissues and through age-matched control studies.
Journal of intellectual disability research : JIDR, 2025 · doi:10.1111/jir.13197