From VIZ:
Kohske made her manga debut in 2009 with the short story "Postman" in Shonen GanGan magazine. Her first series, Gangsta., began running in Monthly Comic Bunch in 2011 and became an instant hit.
More about her work can be found on her website
KAMO Syuhei worked as her assistant.
Taken from the author's official tweet about her condition and Gangsta's hiatus:
"I'm manga artist and have systemic lupus erythematosus. Due to complications, I lost one eye. I also have paralysis in my fingers, disorders in blood vessels and internal organs.
I'm still working, but it's much slower than a typical manga artist, and updates are irregular. This account publishes illustrations drawn as part of rehabilitation. The whole picture of the illustration is available for a fee on "FANBOX".
I prioritize my health over work, so I want you to leave me alone. I'm crazy now to enjoying life with the my little birds."