Complex sentence: Interstitial cystitis, or bladder pain syndrome (also IC/BPS), is a chronic inflammatory condition of the submucosal and muscular layers of the bladder of unknown cause and is regarded as a diagnosis of exclusion.
Split into simpler sentences: Interstitial cystitis, or bladder pain syndrome (also IC/BPS), is a chronic inflammatory condition of the submucosal and muscular layers of the bladder. The cause of IC/BPS is currently unknown and the condition is regarded as a diagnosis of exclusion.