<P>PROBLEM TO BE SOLVED: To provide an advanced identification of neurotrophic factor to diagnose and treat disorders of nerve systems. <P>SOLUTION: An isolated neublastin nucleic acid containing a sequence selected from a group consisted of (a) a nucleotide sequence of sequence No.1, (b) a neublastin polypeptide containing at least 90% homogeneity to sequence No.2 AA<SB>1</SB>-AA<SB>105</SB>, or a nucleotide sequence containing an open reading frame encoding at expression time for a polypeptide derived therefrom, (c) a nucleotide specifically hybridizes under a high stringency solution hybridization condition to the nucleotide containing sequence No.1 nucleotide sequence or its mutually complementary strand, and (d) a nucleotide at least 70% homogenous with the polynucleotide sequence existing as sequence No.1. <P>COPYRIGHT: (C)2008,JPO&INPIT 
NEUROTROPHIC FACTOR