Glycosaminoglycans (GAGs) are present in
proteoglycans, which play critical physiological roles in various tissues. They are known to be elevated in
mucopolysaccharidoses (MPS), a group of rare inherited
metabolic diseases in which the lysosomal
enzyme required to break down one or more GAG is deficient. In a previous study, we found elevation of GAGs in a subset of patients without MPS. In the current study, we aim to investigate serum GAG levels in patients with conditions beyond MPS. In our investigated samples, the largest group of patients had a clinical diagnosis of viral or non-viral
encephalopathy. Clinical diagnoses and conditions also included
epilepsy,
fatty acid metabolism disorders, respiratory and renal disorders, liver disorders,
hypoglycemia, developmental disorders, hyperCKemia,
myopathy,
acidosis, and
vomiting disorders. While there was no conclusive evidence across all ages for any disease, serum GAG levels were elevated in patients with
encephalopathy and some patients with other conditions. These preliminary findings suggest that serum GAGs are potential
biomarkers in MPS and other disorders. In conclusion, we propose that GAGs elevated in blood can be used as
biomarkers in the diagnosis and prognosis of various diseases in childhood; however, further designed experiments with larger sample sizes are required.