{
  "id": 11255067,
  "title": "Multimodal MRI Clustering Reveals an Elevated Free-Water Biotype in Autism with Increased Social Symptoms",
  "url": "https://urgent.news/2026/10/01/multimodal-mri-clustering-reveals-an-elevated-free-water-biotype-in",
  "topic": "health",
  "section": "Health & Medicine",
  "published": "2026-10-01T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.09.25.754196v1?rss=1"
  },
  "original_language": "en",
  "account": "Autism spectrum disorder (ASD) is a neurobiologically diverse condition, and analyzing these individuals in groups may obscure effects specific to certain subgroups. A study aimed to determine if there are unique subtypes within ASD using unsupervised clustering of multimodal MRI data. The researchers analyzed 149 participants with ASD and 129 typically developing (TD) controls from the Autism Brain Imaging Data Exchange II, which included 6 sites and participants aged 5 to 64 years. The MRI data included measures of free water (FW), tissue anisotropy, diffusion tensor imaging analysis along the perivascular space (DTI-ALPS), cerebrospinal fluid (CSF) volumes, and resting-state regional homogeneity.\n\nThe ASD participants were clustered using k-means clustering based on either global (7 features) or regional (17 features) sets. The robustness of the clustering was assessed using permutation tests and two additional algorithms. The TD participants were subsequently projected to evaluate the specificity of the identified clusters. The researchers then correlated the composite imaging score with Social Responsiveness Scale (SRS) subscales, symptom severity, and IQ, while correcting for multiple comparisons using false discovery rate.\n\nThe findings revealed a distinct biotype within the ASD group characterized by an elevated free-water (EFW) composition. This subgroup made up approximately 10% of the ASD participants and was defined by significantly increased FW levels (4.91 standard deviations higher than the remaining ASD participants), reduced tissue anisotropy, reduced DTI-ALPS, and enlarged ventricles. This specific biotype was consistently identified across different feature sets and clustering algorithms, showing good reproducibility (permutation p value).",
  "summary": "Background: Autism spectrum disorder (ASD) is neurobiologically heterogeneous, and group comparisons may mask effects confined to subgroups. We tested whether distinct biotypes exist within ASD using unsupervised clustering of multimodal MRI. Methods: We analyzed 149 participants with ASD and 129 typically developing (TD) controls from the Autism Brain Imaging Data Exchange II (6 sites; age 5 to…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}