This cross-sectional study was conducted at a child development center in Northern India in the year 2016-17. Children aged 2-12 years diagnosed with ASD as per DSM-5 criteria were included. Severity of symptoms of ASD was graded as per Childhood Autism Rating Scale [4], and developmental level was graded as per Developmental Profile-3 Manual [5]. Children on gluten-free diet for <1 month or those diagnosed with autoimmune disorders were excluded. After informed consent, history of gastrointestinal symptoms was elicited and pertinent psychological assessments were done. Blood sample (2 mL) was drawn from all participants for estimation of anti-tissue transglutaminase IgA (Anti-TTG–IgA) levels for screening for celiac disease, and serum total IgA levels to exclude IgA deficiency. Anti TTG–IgA was measured using ELISA (Autostat II, Hycor Biomedical, USA). The Upper limit of Normal (ULN) was 7 IU/mL. Serum total IgA was measured using Nephstar Immunoglobulin A (IgA) kit in which tat principle- Immunonephilimetry was applied. Children with low total IgA levels were excluded. Children with raised level of anti TTG-IgA were planned to be tested for HLA-DQ2/DQ8 by PCR and subjected to endoscopic duodenal biopsy. Data were analyzed using SPSS version 23.

A convenience sample of 155 children with ASD was screened. Children with low serum total IgA levels were excluded. The socio-demographic and psychological profile of the study population is shown in Table I. Gastrointestinal symptoms were present in 51 (34%) cases. Recurrent abdominal pain was the most frequent complaint (16.6%), followed by constipation (12.6%), chronic/recurrent diarrhoea (8%), abdominal distension (2%), weight loss (1.3%), and anorexia (1.3%). All the children had anti-TTG levels below the ULN; hence, all were screen negative and no further diagnostic testing in form of duodenal biopsy or HLA evaluation was required.

TABLE I	Socio-demographic and Psychological Profile of the Study Children (N=150)

Two studies from Italy have reported prevalence of celiac disease of around 3% in children with ASD as compared to approximately 1% in the general population [6,7]. Majority of other studies have refuted such association. The limitation of present study was inability to perform anti-gliadin antibodies [8,9]. Some researchers consider ASD to be a manifestation of Non-Celiac Gluten Sensitivity (NCGS) [10], which is a poorly defined entity in which neuro-psychiatric symptoms are triggered by gluten ingestion, in the absence of celiac-specific antibodies or classical villous atrophy on duodenal biopsy, with variable presence of first generation IgA Anti-gliadin antibodies (AGA).

To conclude, there does not seem to be any association between ASD and celiac disease, and there is no rationale for routine screening for celiac disease in ASD. Further studies are warranted to evaluate association of NCGS with ASD and any role of gluten-free diet in such patients.

Contributors: MJ: conceptualized the study. MJ,AK,SK: were involved in designing the study; AK: collected the data and SK performed the biochemical investigations. AK, RJ: reviewed the literature, analyzed the data and drafted the manuscript. MJ, SK: revised the manuscript for important intellectual content. The final manuscript was approved by all authors. All authors will be accountable for all aspects of the work.

Funding: None; Competing interest: None stated.

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