Why is there no above the line category for Sound Designer?

I'm trying to give proper credit to our film's sound designer who's sound design and mix are a key part of the film's success. There is a Sound Department category, but this is for below the line sound roles. Why is there not an above the line category for Sound Design? This role is just as important as the composer and credited above the line in our film. This is a huge oversight with IMDb categories and needs to be corrected. Thanks!