The association between age and CFQ-R total score (left) and medical status (standardised to mean zero and SD one) (right) for patients homozygous or compound heterozygous for Classes I and II (filled circles and solid lines) and those not having these muta... The association between age and CFQ-R total score (left) and medical status (standardised to mean zero and SD one) (right) for patients homozygous or compound heterozygous for Classes I and II (filled circles and solid lines) and those not having these mutation classes (open circles and dotted lines). CFQ-R, Cystic Fibrosis Questionnaire-Revised. Lena Backström-Eriksson et al. BMJ Open Resp Res 2016;3:e000141 ©2016 by British Thoracic Society