Specify Jacobian for nlmefit

Hello! I am currently trying to fit a population model (non-linear mixed effects) on a dataset (longitudinal tumor burden across 45 patients). However, I often get an error that my Jacobian matrix has a zero column vector. I am able to get an analytic solution to the set of ODEs I'm working with, and consequently its Jacobian. Given the analytic solution I can understand how this error might come up. I've tried different parameterizations but to no avail. I'd like to see if specifying the analytic solution of Jacobian matrix will work.

I've looked at other MATLAB functions, such as lsqnonlin and lsqcurvefit, and see how they permit specification of the Jacobian matrix as a functional output.

My question: Is there a way to specify the Jacobian matrix as a functional output to the fun input of nlmefit?