[Turkish infant with hypoelectrolytemia and metabolic alkalosis as the sole manifestations of a mild form of cystic fibrosis (mutation D110H)].

We report the history of an infant who presented with hypotonic dehydration and metabolic alkalosis, in whom the diagnosis of cystic fibrosis was made on the basis of investigations for rare cystic fibrosis mutations. Since no other signs and symptoms of the CF disease were present, the finding of the rare mutation D110H on exon 4 of the CFTR-gene was paramount in the delineation of his underlying illness. He is now thriving well with a daily oral substitution of 1-2 grams of sodium chloride. A mild variant of cystic fibrosis has to be considered in infants presenting with unexplained hypoelectrolytemia and metabolic alkalosis. Like in our child, typical signs and symptoms of cystic fibrosis like maldigestion may not be present. The search has to be extended into "mild" mutations of the disease like D110H which was found in our case.