Diabetes mellitus and cystic fibrosis in 2 Saudi siblings.

Diabetes mellitus and cystic fibrosis (CF) have been reported before in the literature, but they have never been reported in the same patient in the Middle East. We present the first reported case of insulin dependent diabetes mellitus (IDDM) and CF in 2 siblings of the same family. Both siblings were diagnosed early in life with IDDM, and their diabetes was well controlled on insulin. Cystic fibrosis was diagnosed in the first case one year after IDDM was diagnosed due to history of chronic cough and in the 2nd case by family screening. Both had severe failure to thrive, recurrent chest infections and gastro-esophageal reflux. With treatment both showed clinical improvement, but continued to have moderate lung disease radiologically and by pulmonary function test.