Parathormone-independent increased renal tubular calcium reabsorption

What it means

An increase in the reabsorption of calcium by the renal tubulus that is not associated with increased parathormone levels.

This feature is seen with familial hypocalciuric hypercalcemia. This disease has three known genetic etiologies, in type 1 there is a loss of function mutation in the calcium-sensing receptor (encoded by CASR), in type 2 there is a gain of function mutation in GNA11, which is involved in calcium-sensing receptor signaling, and in type 3 there is a mutation in AP2S1, which encodes the adaptor-related protein complex 2, sigma 1 subunit, which alters calcium-sensing receptor endocytosis.

Rare diseases that can present with this1

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions, and Orphanet separately records 1 disease where this sign is specifically absent. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category

Also called: Parathormone-independent increased renal tubular Ca reabsorption · Parathormone-independent increased renal tubular Ca2+ reabsorption