Those patients with genetic hyperabsorption
of iron will require periodic phlebotomies indefinitely to maintain their iron stores at a safe level.
In GIT this altered protein causes decreased secretion of chloride ion and hyperabsorption
of water resulting in thick mucous fecal material.
(1,2) Mutations of the CF transmembrane conductance regulator (CFTR) gene lead to a defective secretion of chloride and a hyperabsorption
Hypervitaminosis D mediates compensatory [Ca.sup.2+] hyperabsorption
in TRPV5 Knockout mice.
Targeted deletion of hepcidin gene in mice or mutations in human gene result in elevated body iron stores, presumably due to hyperabsorption
associated with decreased iron in tissue macrophages (39).
Hereditary hemochromatosis, one of the most common genetic diseases in Caucasians, is characterized by excessive iron deposition secondary to hyperabsorption
of dietary iron and can potentially can lead to multiorgan failure if untreated.
On the other hand, a series of gastrointestinal disturbances such as inflammatory bowel disease, small bowel resection, or jejunoileal bypass (connection of the duodenum to the colon) may set up the patient for hyperabsorption
of oxalate from dietary sources and increase the incidence of stones.
Increased intestinal vitamin D receptor in genetic hypercalciuric rats: a cause of intestinal calcium hyperabsorption
. J Clin Investig 1993;91: 661-7.