Provided herein are methods and kits for analyzing a biological sample obtained from a subject having, suspected of having, or being at risk for a disease associated with the contact activation system.

There is provided a method for diagnosing a subject with early onset muscle atrophy, said method comprising: obtaining a biosample from the subject; and assaying the biosample for one or more biomarkers, said one more biomarkers are taurine, proline, citrulline, trigonelline, thymidine, ornithine, glutamate, L-pyroglutamic acid, creatinine, adenine, nicotinamide, 2-methylhippuric acid, maltol, L-arginine, hypotaurine, L-glutamine, homogentisic acid, methylhistidine, oxoglutaric acid, xanthine, L-carnitine, succinate, or a combination thereof; and identifying the subject with early onset muscle atrophy on the basis of a deviation in the one or more of said one more biomarkers.

Nutritive Polypeptides are provided herein. Also provided are various other embodiments including nucleic acids encoding the polypeptides, recombinant microorganisms that make the polypeptides, vectors for expressing the polypeptides, methods of making the polypeptides using recombinant microorganisms, compositions and formulations that comprise the polypeptides, and methods of using the polypeptides, compositions and formulations.