13G Filing: Park West Asset Management and Invitae Corp (NVTA)

Exhibit A

JOINT FILING AGREEMENT

In accordance with Rule
13d-1(k) under the Securities Exchange Act of 1934, as amended, the persons named below agree to the joint filing on behalf of
them of a statement on Schedule 13G (including amendments thereto) with respect to the shares of Common Stock, $0.0001
par value per share, of Invitae Corporation, a Delaware corporation, and further agree that this Joint Filing Agreement be included
as Exhibit A to such Schedule 13G. In evidence thereof, the undersigned hereby execute this agreement this 1st day of December,
2017.