  In the curvaton model of inflation, where a second scalar field, the
"curvaton", is responsible for the observed inhomogeneity, a non-zero neutrino
degeneracy may lead to a characteristic pattern of isocurvature perturbations
in the neutrino, cold dark matter and baryon components. We find the current
data can only place upper limits on the level of isocurvature perturbations.
These can be translated into upper limits on the neutrino degeneracy parameter.
In the case that lepton number is created before curvaton decay, we find that
the limit on the neutrino degeneracy parameter is comparable with that obtained
from Big-bang nucleosynthesis. For the case that lepton number is created by
curvaton decay we find that the absolute value of the non-Gaussianity
parameter, |f_nl|, must be less than 10 (95% confidence interval).
