title: Congenital sucrase-isomaltase deficiency presenting with failure to thrive, hypercalcemia, and nephrocalcinosis.
abstract: BACKGROUND
  Disaccharide Intolerance Type I (Mendelian Interance in Man database: *222900) is a rare inborn error of metabolism resulting from mutation in sucrase-isomaltase (Enzyme Catalyzed 3.2.1.48). Usually, infants with SI deficiency come to attention because of chronic diarrhea and nutritional evidence of malabsorption.
  
  
  METHODS
  We describe an atypical presentation of this disorder in a 10-month-old infant. In addition to chronic diarrhea, the child displayed severe and chronic hypercalcemia, the evaluation of which was negative. An apparently coincidental right orbital hemangioma was detected. Following identification of the SI deficiency, an appropriately sucrose-restricted, but normal calcium diet regimen was instituted which led to cessation of diarrhea, substantial weight gain, and resolution of hypercalcemia.
  
  
  CONCLUSIONS
  This case illustrates that, similar to congenital lactase deficiency (Mendelian Interance in Man database: *223000, Alactasia, Hereditary Disaccharide Intolerance Type II), hypercalcemia may complicate neonatal Sucrase-Isomaltase deficiency. Hypercalcemia in the presence of chronic diarrhea should suggest disaccharide intolerance in young infants.
authors.affiliation: Department of Molecular Genetics, Baylor College of Medicine, Houston, TX 77030, USA. jbelmont@bcm.tmc.edu
authors.forename: John W
authors.initials: JW
authors.lastname: Belmont
authors.forename: Barbara
authors.initials: B
authors.lastname: Reid
authors.forename: William
authors.initials: W
authors.lastname: Taylor
authors.forename: Susan S
authors.initials: SS
authors.lastname: Baker
authors.forename: Warren H
authors.initials: WH
authors.lastname: Moore
authors.forename: Michael C
authors.initials: MC
authors.lastname: Morriss
authors.forename: Susan M
authors.initials: SM
authors.lastname: Podrebarac
authors.forename: Nancy
authors.initials: N
authors.lastname: Glass
authors.forename: I David
authors.initials: ID
authors.lastname: Schwartz
mesh_terms: D002118:Calcium / Q000097:blood*; D002239:Carbohydrate Metabolism, Inborn Errors / Q000175:diagnosis*; D005183:Failure to Thrive / Q000209:etiology*; D005260:Female; D006801:Humans; D007223:Infant; D009397:Nephrocalcinosis / Q000209:etiology*; D013394:Sucrase-Isomaltase Complex / Q000172:deficiency*; D013395:Sucrose / Q000378:metabolism*
chemical_list: D013395:Sucrose; D013394:Sucrase-Isomaltase Complex; D002118:Calcium