Rajesh, according to Disability rules listed in page no# 71 of https://ntaneet.nic.in/ntaneet/ShowPdf.aspx, Sickle cell illness is eligible for PWD reservation subjective to the medical certificate from the District Medical College. There is no vertical reservation for PWD. It is a horizontal reservation within your Category. So if you have a PWD certificate and you get a seat in MBBS under PWD quota, you can take admission in MBBS.