Neurensin-1 (NRSN1), also designated Vesicular membrane protein of 24 kDa (VMP) or Neuro-p24, is a 195 amino acid multi-pass membrane protein belonging to the VMP family that is involved in the transport of neural organelle transport and in the transduction of nerve signals or in nerve growth. Expressed solely in brain, Neurensin-1 is also thought to play a role in neurite extension. The gene encoding Neurensin-2 maps to human chromosome 6, which contains around 1,200 genes within 170 million base pairs of sequence. Deletion of a portion of the q arm of chromosome 6 is associated with early onset intestinal cancer suggesting the presence of a cancer susceptibility locus. Porphyria cutanea tarda, Parkinson's disease, Stickler syndrome, 21-hydroxylase deficiency and maple syrup urine disease are also associated with genes on chromosome 6.