Mosaic pattern of sucrase isomaltase deficiency in two brothers

TY - JOUR

T1 - Mosaic pattern of sucrase isomaltase deficiency in two brothers

AU - Reinshagen, Konrad

AU - Keller, Klaus M

AU - Haase, Bianca

AU - Leeb, Tosso

AU - Naim, Hassan Y

AU - Zimmer, Klaus P

PY - 2008/1

Y1 - 2008/1

N2 - The pathophysiology of mucosal changes observed in infants with chronic protracted diarrhea is poorly understood. We report on two brothers suffering from a special form of sucrase isomaltase (SI) deficiency. The children presented with weight loss and dyspepsia after sucrose exposition. We performed an H respiration test, which showed a pathologic result in the younger brother. Analysis of the brush border enzyme activities showed low expression of lactase and SI. Immunoelectron microscopy of duodenal biopsies showed an isolated SI deficiency in a mosaic pattern [e.g., 42% (14%) crypt enterocytes and 64% (59%) villus enterocytes with decreased amounts of SI on microvilli], whereas lactase and aminopeptidase n (ApN) were present at the apical membrane of all cells in a normal range. The SI mosaic pattern of these patients shows that the enterocytes contain low amounts of SI on the apical membrane but express normal quantities of other disaccharidases. These findings suggest the existence of different clonal expressions or specific (posttranslational) mechanisms of postGolgi transportation for individual brush border enzymes. It remains unresolved whether the mosaic distribution is part of a normal maturation process or caused by a lack of an overall control mechanism in the expression of brush border hydrolases.

AB - The pathophysiology of mucosal changes observed in infants with chronic protracted diarrhea is poorly understood. We report on two brothers suffering from a special form of sucrase isomaltase (SI) deficiency. The children presented with weight loss and dyspepsia after sucrose exposition. We performed an H respiration test, which showed a pathologic result in the younger brother. Analysis of the brush border enzyme activities showed low expression of lactase and SI. Immunoelectron microscopy of duodenal biopsies showed an isolated SI deficiency in a mosaic pattern [e.g., 42% (14%) crypt enterocytes and 64% (59%) villus enterocytes with decreased amounts of SI on microvilli], whereas lactase and aminopeptidase n (ApN) were present at the apical membrane of all cells in a normal range. The SI mosaic pattern of these patients shows that the enterocytes contain low amounts of SI on the apical membrane but express normal quantities of other disaccharidases. These findings suggest the existence of different clonal expressions or specific (posttranslational) mechanisms of postGolgi transportation for individual brush border enzymes. It remains unresolved whether the mosaic distribution is part of a normal maturation process or caused by a lack of an overall control mechanism in the expression of brush border hydrolases.

KW - CD13 Antigens/analysis

KW - Carbohydrate Metabolism, Inborn Errors/enzymology

KW - Child

KW - Duodenum/enzymology

KW - Enterocytes/enzymology

KW - Genotype

KW - Humans

KW - Lactase/analysis

KW - Male

KW - Microvilli/enzymology

KW - Mosaicism

KW - Pedigree

KW - Phenotype

KW - Siblings

KW - Sucrase-Isomaltase Complex/analysis

U2 - 10.1203/PDR.0b013e31815b4bac

DO - 10.1203/PDR.0b013e31815b4bac

M3 - SCORING: Journal article

C2 - 18043509

VL - 63

SP - 79

EP - 83

JO - PEDIATR RES

JF - PEDIATR RES

SN - 0031-3998

IS - 1

ER -