Comparison of urine glycosaminoglycan excretion between children with autism spectrum disorder and typically developed children

Background

Abnormalities pertaining to glycosaminoglycan metabolism have been demonstrated in children with autism spectrum disorder. The aim of the present study was to compare urine excretion of sulfated glycosaminoglycans in children with autism spectrum disorder, with neurotypical controls and explore its association with co-occurring symptoms.

Method

Random urine samples were collected from children with autism spectrum disorder (n = 61) between the ages of 2 and 6 years, and age- and sex-matched neurotypical controls. Urine glycosaminoglycan levels were quantified by the dimethylmethylene blue (DMMB) dye-binding assay.

Results

Mean glycosaminoglycan/creatinine ratio of children with autism spectrum disorder was 22.279 ± 13.044 mg/mmol while that of neurotypical controls was 19.121 ± 7.319 mg/mmol. Eight patients with autism spectrum disorder (13.11%) exhibited abnormally high glycosaminoglycan excretion. Unstandardized urine glycosaminoglycan levels are significantly higher (p = 0.019) in the autism spectrum disorder group when covariates such as age, urinary creatinine, and height are taken into consideration by ANCOVA. However, the outcome showed a trend towards significance when glycosaminoglycan/creatinine ratio was used in ANCOVA (p = 0.058). In neurotypical subjects, the urine glycosaminoglycan levels appear to decline with age, height, and weight while this trend was not apparent in subjects with autism spectrum disorder. Glycosaminoglycan excretion did not correlate with the presence of co-occurring symptoms of autism spectrum disorder; frequent gastrointestinal symptoms, self-injurious behaviors, food aversions, or parent-reported sleep problems.

Conclusions

A subset of children with autism spectrum disorder exhibits higher urine glycosaminoglycan excretion. Further research is needed to explore the molecular basis of this finding.