SNP Shot: Genomic Insights

Familial isolated hyperparathyroidism (FIHP) is a genetic disorder where the parathyroid glands become overactive (hyperparathyroidism). These four glands, located in the neck, produce parathyroid hormone, which controls blood calcium levels. In FIHP, one or more parathyroid glands produce too much parathyroid hormone, leading to high blood calcium (hypercalcemia). Parathyroid hormone increases calcium release from bones and calcium absorption from food, both of which increase calcium in the bloodstream.

The overproduction of parathyroid hormone in FIHP is due to tumors on the parathyroid glands. Usually, only one gland is affected, but sometimes multiple glands develop tumors. These tumors are usually non-cancerous (benign) and are called adenomas. Rarely, the tumors are cancerous, called parathyroid carcinoma. Because the problem stems from the parathyroid glands themselves, FIHP is classified as a type of primary hyperparathyroidism.

The imbalanced calcium levels caused by the overactive parathyroid glands lead to symptoms like kidney stones, nausea, vomiting, high blood pressure (hypertension), weakness, and fatigue. Hyperparathyroidism also weakens bones (osteoporosis) as calcium is drawn from them into the blood. FIHP can be diagnosed at any age, from childhood to adulthood. Often, the first sign is elevated calcium detected in a routine blood test, even before other symptoms appear.

Inheritance:

FIHP is usually inherited in an autosomal dominant manner. This means that having just one copy of the mutated gene in each cell is enough to cause the condition.