A patient interface system to treat a respiratory disorder of a patient, the patient interface system comprising: a positioning and stabilising structure including a back portion (3302; 3340.1; 3350.1; 3360.1) and a pair of upper straps (3312, 3314; 3346, 3341; 3356, 3351; 3366, 3361) extending from the back portion and a pair of lower straps (3316, 3318; 3344; 3354; 3364); and a patient interface including a plenum chamber and a seal-forming structure; and a patient interface frame to connect the patient interface to the positioning and stabilising structure, the patient interface frame including a pair of rigidiser arms (3371, 3381), each rigidiser arm extending from the patient interface frame at a respective connection point (3391, 3393) located in a plane substantially parallel to the patient's Frankfort horizontal plane, the patient interface frame and the pair of rigidiser arms being molded in one piece, the pair of rigidiser arms (3371, 3381) further including a pair of upper attachment points (3375, 3385), and the patient interface frame further comprising a pair of lower attachment points (3372, 3374) for releasable attachment to a respective lower strap, said lower attachment points (3372, 3374) being joined to the patient interface frame and being separate from the rigidiser arms (3371, 3381), wherein, when the patient interface system is donned by the patient, the pair of upper attachment points (3375, 3385) is vertically offset relative to the connection points (3391, 3393); wherein the pair of upper straps (3312, 3314; 3346, 3341; 3356, 3351; 3366, 3361) are adapted to be releasably attached to the pair of upper attachment points (3375, 3385) such that, when donned by the patient, the pair of upper straps are parallel to the patient's Frankfort horizontal plane, and wherein the patient interface does not include a forehead support. a positioning and stabilising structure including a back portion (3302; 3340.1; 3350.1; 3360.1) and a pair of upper straps (3312, 3314; 3346, 3341; 3356, 3351; 3366, 3361) extending from the back portion and a pair of lower straps (3316, 3318; 3344; 3354; 3364); and a patient interface including a plenum chamber and a seal-forming structure; and a patient interface frame to connect the patient interface to the positioning and stabilising structure, the patient interface frame including a pair of rigidiser arms (3371, 3381), each rigidiser arm extending from the patient interface frame at a respective connection point (3391, 3393) located in a plane substantially parallel to the patient's Frankfort horizontal plane, the patient interface frame and the pair of rigidiser arms being molded in one piece, the pair of rigidiser arms (3371, 3381) further including a pair of upper attachment points (3375, 3385), and the patient interface frame further comprising a pair of lower attachment points (3372, 3374) for releasable attachment to a respective lower strap, said lower attachment points (3372, 3374) being joined to the patient interface frame and being separate from the rigidiser arms (3371, 3381), wherein, when the patient interface system is donned by the patient, the pair of upper attachment points (3375, 3385) is vertically offset relative to the connection points (3391, 3393); wherein the pair of upper straps (3312, 3314; 3346, 3341; 3356, 3351; 3366, 3361) are adapted to be releasably attached to the pair of upper attachment points (3375, 3385) such that, when donned by the patient, the pair of upper straps are parallel to the patient's Frankfort horizontal plane, and wherein the patient interface does not include a forehead support.