A Boy With Severe Infantile Gastrogen Lactose Intolerance and Acquired Lactase Deficiency

Abstract

A 10-year-old boy with severe familial lactose intolerance in infancy (vomiting, failure to thrive, lactosuria (5.25 g/l), sucrosuria (12 g/l), and aminoaciduria. Intestinal disaccharidases (including lactase and sucrase) normal at age 6 and 20 weeks. Oral lactose tolerance test at this age resulted in lactosuria (4.6 g/l); sucrose tolerance test, in sucrosuria (18.5 g/l). In contrast, intraduodenal lactose tolerance test gave only low lactose excretion in urine (0.28 g/l). He improved rapidly and had no lactosuria on intraduodenal feeding with citric acid milk. The lactosuria diminished as age increased, but was still higher at age 6 years than that of controls. He tolerated normal disaccharide containing food after 1.5 years of age. At 5.5 to 6 years, he had symptoms of lactose malabsorption, and an isolated lactase deficiency was proved. At 10 years, he still tolerates only limited amounts of milk. The defect in severe familial infantile lactose intolerance seems to be localized in the gastric mucosa. Acquired lactase deficiency can appear later in childhood in this syndrome.

Benign Disacchariduria

“…In 1954, three patients with mental retardation, hiatus hernia, and sucrosuria were described (1) and later an additional twelve patients with a rather similar presentation were reported (2) although the possible causal relationship between the mellituria and the mental retardation was clearly and properly dismissed. Two groups of workers have now demonstrated that the lactosuria of familial lactose intolerance can be circumvented by intraduodenal feeding, and have suggested that the abnormality in the absorption of the disaccharide (2) was localized to the gastric mucosa (3,4).…”