Fungi

Abstract

Gastrointestinal (GI) symptoms often affect children with autism spectrum disorders (ASD) and GI symptoms have been associated with an abnormal fecal microbiome. There is limited evidence of Candida species being more prevalent in children with ASD. We enrolled 20 children with ASD and GI symptoms (ASD + GI), 10 children with ASD but no GI symptoms (ASD − GI), and 20 from typically developing (TD) children in this pilot study. Fecal mycobiome taxa were analyzed by Internal Transcribed Spacer sequencing. GI symptoms (GI Severity Index [GSI]), behavioral symptoms (Social Responsiveness Scale -2 [SRS-2]), inflammation and fungal immunity (fecal calprotectin and serum dectin-1 [ELISA]) were evaluated. We observed no changes in the abundance of total fungal species (alpha diversity) between groups. Samples with identifiable Candida spp. were present in 4 of 19 (21%) ASD + GI, in 5 of 9 (56%) ASD − GI, and in 4 of 16 (25%) TD children (overall P = 0.18). The presence of Candida spp. did not correlate with behavioral or GI symptoms (P = 0.38, P = 0.5, respectively). Fecal calprotectin was normal in all but one child. Finally, there was no significance in serum dectin-1 levels, suggesting no increased fungal immunity in children with ASD. Our data suggest that fungi are present at normal levels in the stool of children with ASD and are not associated with gut inflammation.

The search for gastrointestinal inflammation in autism: a systematic review and meta-analysis of non-invasive gastrointestinal markers

“…Of the 12 peer-reviewed studies examining stool calprotectin in autism, one study did not include comparisons with a control group [ 35 ] and three studies could not be included in the meta-analysis as relevant summary statistics could not be retrieved [ 36 – 38 ]. Median calprotectin levels of 77.12 μg/g (IGR = 135.69 μg/g) were found in a study of 80 autistic preschoolers participating in a trial of probiotic supplementation [ 35 ].…”

“…This study found that calprotectin levels were not significantly different between preschoolers with and without GI symptoms. In the remaining three studies, no differences were found between levels of calprotectin in autistic children and adolescents relative to non-autistic controls [ 37 , 38 ], siblings or first-degree relatives [ 36 , 37 ].…”

“…De Magistris et al [ 36 ] found elevated calprotectin levels in 24.6% of their participants; however, GI symptom severity was not examined in their study. It is likely however that not all GI symptoms are associated with higher levels of calprotectin, and calprotectin levels did not discriminate between autistic children with GI symptoms and those without in the small studies that have been carried out to date [ 35 , 38 , 43 ]. In assessing GI symptoms in autistic populations, it is important to consider that the ways in which autistic children communicate the presence of GI discomfort will differ based on their verbal ability [ 3 ].…”

Bimodal distribution ofCandida albicansin children with Autism linked with ASD symptoms

“…Among fungi, a higher abundance of Aspergillus was reported in one ASD child (a case report) 22 , but in contrast, a lower abundance of Aspergillus versicolor was found in 29 ASD children compared to 31 TD 20 . Whereas, for yeast, a higher abundance of Candida specifically C. albicans was consistently observed in children with ASD compared to controls 18,19,21 .…”

“…The copyright holder for this preprint (which this version posted July 14, 2023. ; https://doi.org/10.1101/2023.07. 13.548908 doi: bioRxiv preprint 25-58% of children with ASD, at rates substantially higher than in TD individuals 3,[17][18][19][20][21] .…”