Congenital chloride diarrhea

Abstract

Congenital chloride diarrhea is an autosomal recessive congenital disease caused by a mutation in the SLC26A3 gene mapped to chromosome 7 (locus 7q22-q31). At the beginning of the 21st century, more than 250 cases of congenital chloride diarrhea have been reported, mostly in Finland, Poland, Kuwait, and Saudi Arabia, single cases appear all over the world.

SLC26A3 gene encodes an intestinal Cl–/HCO3 – exchanger, а defect of which causes malabsorption of Cl– in the ileum and colon. The disease can be revealed during pregnancy by polyhydramnios, dilated intestinal loops of the fetus on sonography.Most children are born prematurely. Visualization of distended bowel loops and the absence of meconium after birth often leads to unnecessary surgical intervention due to suspected intestinal obstruction or Hirschprung’s disease. The main features of the disease are watery diarrhea, dehydration, failure to thrive, hypochloremia, hyponatremia, hypokalemia and metabolic alkalosis. Fecal chloride excretion is higher than total sodium and potassium excretion. Treatment consists of potassium chloride and sodium chloride replacement therapy. Nowadays patients with adequate treatment reach adulthood but the long-term prognosis is unknown. Therapy stops electrolyte disturbances, but diarrhea persists.

Since 2003, we have observed 3 patients with clinical signs of congenital chloride diarrhea with further confi rmation of a mutation in the SLC26A3 gene. All the children were born prematurely, the mothers had polyhydramnios during pregnancy, and the fetus had dilated bowel loops on ultrasound examination in utero. Two patients underwent surgical treatment because of suspected intestinal obstruction or Hirschsprung’s disease in early neonatal period. Before salt substitution therapy, all children had watery diarrhea, failure to thrive and delayed psychomotor development. We have been observing one of our patients for fi ve years from the moment of diagnosis until now. The girl receives therapy with sodium chloride and potassium chloride, her physical and psychomotor development corresponds to her age, there are no electrolyte abnormalities.