摘要To the editor:We read with a great interest the article by Cai et al.1 They described a good case of Klinefelter's syndrome (KS) with diabetes mellitus (DM).KS is a common abnormality of the sex chromosome,characterized by small testicles,sparse body hair,gynecomastia and hypogonadism in men with two or more X chromosomes.There has been an increased risk of DM,osteoporosis2 and autoimmune disease 3 for KS patients.We report a KS patient accompanying refractory asthma,DM and osteoporosis with a rib fracture.A 43-year-old man was admitted to our hospital for an acute exacerbation of asthma in November 2010.He has suffered from asthma from an age of 3 years,and has been steroid dependent in the past 5 years.Prednisone 20 mg/d alleviated his symptoms and reduced incidences of recurrent attacks.He had a past history of type 2 DM and rib fracture without any trauma.