The present invention relates to compositions and methods of GDNF fusion polypeptides, wherein the GDNF fusion polypeptides include an Fc domain, an albumin-binding peptide, a fibronectin domain, or a human serum albumin, joined to a GDNF variant either directly or by the way of a linker. The GDNF fusion polypeptides may used to treat metabolic diseases, such as obesity and Type-1 and Type-2 diabetes, and neurological diseases, such as Amyotrophic lateral sclerosis (ALS) and Parkinson's disease.
