How is Trehalase Deficiency Diagnosed?

The gene of human lactase phlorizin hydrolase is located on chromosome 2. When the brush border of the small intestinal mucosa of infants lacks lactase, watery diarrhea will occur after the first breastfeeding.

The most common disaccharidase deficiency in adults is lactase deficiency. Lactase activity is highest in newborns and can be reduced to 10% of its maximum amount later. Adults with lactase deficiency are at this level. After infants are weaned, lactase gradually decreases, and diarrhea is easily caused when they take milk again. The deficiency of this enzyme is related to genetics, accounting for 5% to 30% in Caucasians and 75% in people of color, including Asians and Africans. Sucrose-isomaltase deficiency can be reduced to 10% to 20% of normal, and the intestinal mucosa is normal. The reason is still unknown. In addition, during gastrointestinal infections, disaccharidase can also be temporarily under-secreted.

Differential diagnosis of trehalase deficiency:

Various secondary lactase deficiencies such as celiac disease, extensive small intestinal resection, Whipple's disease, Crohn's disease, giardiasis, small intestinal lymphosarcoma, small intestinal malignant lymphoma and malabsorption caused by certain drugs (such as alcohol, neomycin, cholestyramine) should be excluded.

1. Celiac disease: Gluten-induced enteropathy, also known as coeliac disease and nontropical steatorrhea, has a high incidence in North America, Northern Europe, and Australia, but is rare in China. The male-female ratio is 1:1.3-2.0, with more females than males. It can occur at any age, with the peak age of onset being children and young people, but in recent years the number of elderly people suffering from this disease has been increasing.

2. Whipple's disease: Whipple's disease is an uncommon chronic bacterial infection that affects multiple systems. It usually affects the small intestine, with prominent gastrointestinal symptoms. Typically, the intestinal mucosa is infiltrated by foamy macrophages containing periodic acid (PAS)-positive substances, and the villi are deformed. Under an electron microscope or a high-resolution optical microscope, bacteria can be seen in the lamina propria, and PAS-positive macrophages and bacteria can appear outside the intestine, such as in the lymph nodes, spleen, liver, central nervous system, heart, and synovium.

3. Crohn's disease: Crohn's disease is a gastrointestinal granulomatous inflammatory disease of unknown etiology. Currently, this disease and ulcerative colitis are collectively referred to as inflammatory bowel disease. The lesions are mostly seen in the terminal ileum and adjacent colon, often with segmental distribution. The age of onset is mostly between 15 and 40 years old, and males are slightly more likely to be affected than females. The etiology is still unknown, and it is currently believed that this disease may be the result of the combined effects of multiple factors.