Cystic fibrosis related diabetes: Nutrition and growth considerations.

Nutritional considerations are crucial to the optimal management of cystic fibrosis related diabetes (CFRD). The development of abnormal glucose tolerance and CFRD can have negative effects on CF nutritional status. Treatment of CFRD with insulin replacement is essential; however, medical nutrition therapy is important to maintain nutritional status while normalizing blood glucose levels. CF Foundation Nutritional Guidelines are recommended for the nutritional management of CFRD; specifically, the diet should be high in calories, protein, fat, and salt. Carbohydrate intake is not limited, but carbohydrate counting can be used to guide insulin dosing and maintain consistent blood glucose levels. CFTR modulator therapy shows early promise for the improvement of growth and nutritional parameters in CF.

Hypophosphatemic rickets: lessons from disrupted FGF23 control of phosphorus homeostasis.

Fibroblast growth factor-23 (FGF23) regulates phosphate reabsorption in the kidney and therefore plays an essential role in phosphate balance in humans. There is a host of defects that ultimately lead to excess FGF23 levels and thereby cause renal phosphate wasting and hypophosphatemic rickets. We describe the genetic, pathophysiologic, and clinical aspects of this group of disorders with a focus on X-linked hypophosphatemia (XLH), the best characterized of these abnormalities. We also discuss autosomal dominant hypophosphatemic rickets (ADHR), autosomal recessive hypophosphatemic rickets (ARHR) and tumor-induced osteomalacia (TIO) in addition to other rarer FGF23-mediated conditions. We contrast the FGF23-mediated disorders with FGF23-independent hypophosphatemia, specifically hypophosphatemic rickets with hypercalciuria (HHRH). Errant diagnosis of hypophosphatemic disorders is common. This review aims to enhance the recognition and appropriate diagnosis of hypophosphatemia and to guide appropriate treatment.