Pseudo-Bartter's (PB) syndrome characterized by hypokalemic metabolic alkalosis and persistent failure to thrive constitutes a rare typical presentation of cystic fibrosis (CF) with prevalence of 16.8%. We present a case of CF presenting with failure to thrive, dehydration, PB syndrome associated with chest infection and primo-colonization with Pseudomonas aeruginosa. Sweat chloride test was 102 mmol/L. DNA analysis identified 2 mutations 3849 + 1G>A (intron 19) and 4382delA (exon 24) present in heterozygous status. To the best of our knowledge, our case is the first reported case in the literature of CF manifested by PB syndrome associated with chest infection and primo-colonization with Pseudomonas aeruginosa. CONCLUSION: The genotype 3849 + 1G>A/4382delA found in our patient is described for the first time in the literature. It explains the lung involvement with the dehydration and electrolyte disturbances. The role of the mutation in exon 24 in cases of CF with PB syndrome remains to be determined.

© 2011 The Author(s)/Acta Paediatrica © 2011 Foundation Acta Paediatrica.