Sucrose intolerance or genetic sucrase-isomaltase deficiency (GSID) is the condition in which sucrase-isomaltase, an enzyme needed for proper metabolism of sucrose (sugar) and starch (e.g., grains), is not produced or the enzyme produced is either partially functional or non-functional in the small intestine. All GSID patients lack fully functional sucrase, while the isomaltase activity can vary from minimal functionality to almost normal activity. The presence of residual isomaltase activity may explain why some GSID patients are better able to tolerate starch in their diet than others with GSID. Signs and symptoms
Abdominal cramps and bloating
Diarrhea and constipation
Vomiting
Hypoglycemia and headaches
Poor weight gain and growth
Upper respiratory tract and viral diseases
Anxiety and heart palpitations
Excess gas production

Cause
Sucrose intolerance can be caused by genetic mutations in which both parents must contain this gene for the child to carry the disease (so-called primary sucrose intolerance). Sucrose intolerance can also be caused by irritable bowel syndrome, aging, or small intestine disease (secondary sucrose intolerance). There are specific tests used to help determine if a person has sucrose intolerance. The most accurate test is the enzyme activity determination, which is done by biopsying the small intestine. This test is a diagnostic for GSID.
Mastocytosis, a type of mast cell disease, is a rare disorder affecting both children and adults caused by the accumulation of functionally defective mast cells (also called mastocytes) and CD34+ mast cell precursors.People affected by mastocytosis are susceptible to a variety of symptoms, including itching, hives, and anaphylactic shock, caused by the release of histamine and other pro-inflammatory substances from mast cells. Signs and symptoms
When mast cells undergo degranulation, the substances that are released can cause a number of symptoms that can vary over time and can range in intensity from mild to severe. Because mast cells play a role in allergic reactions, the symptoms of mastocytosis often are similar to the symptoms of an allergic reaction. They may include, but are not limited to
Fatigue
Skin lesions (urticaria pigmentosa), itching, and dermatographic urticaria (skin writing)
"Dariers Sign", a reaction to stroking or scratching of urticaria lesions. Abdominal discomfort
Nausea and vomiting
Diarrhea
Olfactive intolerance
Ear/nose/throat inflammation
Anaphylaxis (shock from allergic or immune causes)
Episodes of very low blood pressure (including shock) and faintness
Bone or muscle pain
Decreased bone density or increased bone density (osteoporosis or osteosclerosis)
Headache
Depression
Ocular discomfort
Increased stomach acid production causing peptic ulcers (increased stimulation of enterochromaffin cell and direct histamine stimulation on parietal cell)
Malabsorption (due to inactivation of pancreatic enzymes by increased acid)
HepatosplenomegalyThere are few qualitative studies about the effects of mastocytosis on daily life. However, a Danish study from 2018 describes the multidimensional impact of the disease on everyday life. Pathophysiology
Mast cells are located in connective tissue, including the skin, the linings of the stomach and intestine, and other sites.