Detection of oligosaccharides

1. A method for determining response to a therapy in an individual having an MPS I disorder, the method comprising:

(a) generating a biomarker comprising one or more saturated non-reducing end oligosaccharides, wherein the biomarker is generated by treating a population of a population of glycosaminoglycans, in or isolated from a biological sample from the individual, with at least one digesting glycosaminoglycan lyase, wherein prior to lyase treatment, the biomarker is not present in abundance in samples from individuals with the MPS I disorder relative to individuals without the MPS I disorder; and

(b) using an analytical instrument to detect the presence of and/or measure the amount of the biomarker produced and displaying or recording the presence of or the measure of the biomarker produced;

wherein the biomarker is selected from a group consisting of:

Formula I-A: IdoA-GlcNAc;

Formula I-B: IdoA-GlcNS;

Formula I-C: IdoA-GlcNS6S;

Formula XXI: [IdoA-GlcN(Ac)m-IdoA](SO 3 R) n , where m is 0-1 and n is 0-4;

Formula XXII: [IdoA-GlcN(Ac)m-GlcA](SO 3 R) n , where m is 0-1 and n is 0-3; and

Formula XXIII: [GlcA-GlcN(Ac)m-GlcA](SO 3 R) n , where m is 0-1 and n is 0-3.

2. The method of claim 1 , wherein the biomarker is of Formula I-A: IdoA-GlcNAc.

3. The method of claim 1 , wherein the biomarker is of Formula I-B: IdoA-GlcNS.

4. The method of claim 1 , wherein the biomarker is of Formula I-C: IdoA-GlcNS6S.

5. The method of claim 1 , wherein the method further comprises purifying the biomarker generated in step (a) to yield an isolated population of biomarkers.

6. The method of claim 5 , wherein the biomarker is purified using chromatography or electrophoresis.

7. The method of claim 1 , wherein the method further comprises tagging the biomarkers with a detectable label.

8. The method of claim 7 , wherein the detectable label is a mass label, a radio label, a fluorescent label, a chromophore label, or affinity label.