Familial hypocalciuric hypercalcemia (FHH) is an inherited condition that can cause hypercalcemia, a serum calcium level typically above mg/dL. It is also . Familial hypocalciuric hypercalcemia (FHH) is a generally asymptomatic genetic disorder of phosphocalcic metabolism characterized by lifelong moderate. Familial benign (hypocalciuric hypercalcemia (FHH) is caused by a loss-of- function mutation of one allele of the gene for the calcium-sensing.

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In each of 4 unrelated families with FHH, Chou et al. While the OMIM database is open to the public, users seeking information about a personal medical or genetic condition are urged to consult with a qualified physician for diagnosis and for answers to personal questions. Mutations in G protein-linked receptors: The authors hypcoalciuric that although clinically overt hyperparathyroidism is not observed hypocaociuric the vast majority of FHH cases, this patient could be classified among previously reported FHH patients with parathyroid adenomas.

Familial hypocalciuric hypercalcaemia: a review.

You must be a registered member of Cancer Therapy Advisor to post a comment. The inheritance of FHH is autosomal dominant. Most cases of FHH are associated with loss of function hypercalcemoa in the calcium-sensing receptor CaSR gene, [2] expressed in parathyroid and kidney tissue.

Concentrations of peptide hormones other than parathyroid hormones were common in patients with FHH. Although CASR is diagnostic, there is no treatment for familial hypocalciuric hypercalcemia, so its utility is questionable.

Histologic examination of the parathyroid glands revealed a larger proportion of stromal hhpercalcemia than in normal glands, consistent with previous findings in parathyroid glands from patients with familial benign hypercalcemia. Archived from the original on Hypocalciuric hypercalcemia thus can be caused by either loss of function mutations in the calcium-sensing receptor or reduced function hypecralcemia the receptor resulting from autoantibodies.

An hypercalcemi splice site mutation in the calcium-sensing receptor CASR gene in familial hypocalciuric hypercalcemia and neonatal severe hyperparathyroidism. There are no known factors or medications that affect laboratory results. Nephrolithiasis and peptic ulcer were uncommon. Preliminary localization of a gene for autosomal dominant hypoparathyroidism to chromosome 3q OMIM is intended for use primarily by physicians and other professionals concerned with genetic hypercaldemia, by genetics researchers, and by advanced students in science and medicine.


He was found to have hypocalciuric hypercalcemia with markedly elevated PTH, and a parathyroid adenoma was removed. At a Glance Familial hypocalciuric hypercalcemia is an unusual, usually benign condition that causes chronically elevated serum calcium and reduced calcium excretion.

Summary Epidemiology Prevalence is unknown. Hypocalciuric hypercalcemia, type I. A bonus to all MIMmatch users is the fanilial to sign up for updates on new gene-phenotype relationships. The authors suggested that there might be many families with hypercalcemia due to as yet unidentified CASR mutations manifesting atypical or variable phenotypes, in whom considerations for parathyroid surgery would differ from those for patients with typical FHH.

In addition, these results indicated that NSHPT is not exclusively the result of homozygosity for a mutation that causes familial benign hypercalcemia in the heterozygous state but rather can be due to heterozygosity for mutations at the CASR locus.

Two of the hypercalcemic individuals had a history of renal stones. Unlike primary hyperparathyroidism, hypercalcemia of this origin begins before age 10 years and is not accompanied by urinary stone or renal damage.

They also excluded basic fibroblast growth factorparathyroid hormoneand several other candidate loci. Severe hypercalcemia in a 9-year-old Brazilian girl due to a novel inactivating mutation of the calcium-sensing receptor. Genetic counseling can be offered to family members of affected individuals and genetic screening for the CASR familial mutation. By using this site, you agree to the Terms of Use and Privacy Policy.

The gene responsible for familial hypocalciuric hypercalcemia maps to chromosome 3q in four unrelated families. A Problem for Gene Editing in Cancer? Primary hyperparathyroidism is clinically similar to FHH, apart from the presence of hypercalcemia. However, patients with familial hypocalciuric hypercalcemia may be more sensitive than normal patients to dietary calcium or vitamin D toxicity, so these patients are normally not candidates for the ubiquitous calcium and vitamin D supplementation.


Subtotal parathyroidectomy was performed at 6 weeks; hypercalcemia recurred rapidly, but the bone disease improved gradually with reversion to an asymptomatic state resembling FHH. The distinction between the acquired and hereditary forms is important because glucocorticoids may control the acquired form and parathyroidectomy is rarely necessary for familial hypocalciuric hypercalcemia.

We are determined to keep this website freely accessible. The hypocalciuric or benign variant of familial hypercalcemia: Phenotypic Series Toggle Dropdown.

Familial hypocalciuric hypercalcemia – Wikipedia

FHH is inherited as a dominant trait. This gene encodes the calcium-sensing receptor CaSR.

Only comments seeking to improve the quality and accuracy of information on the Orphanet website are accepted. The grandmother had a parathyroid adenoma surgically removed at age 55 years. The hypercalcemia seen in FHH does not respond to diuretics or bisphosphonates. In asymptomatic hypercalcemia, measure urine calcium, serum PTH and serum magnesium. Powered By Decision Support in Medicine.

This page was last edited on 3 Januaryat In a further study of 5 families, Heath et al. Table 1 Table 1.

Five had had parathyroid surgery. As a result, inhibition of parathyroid hormone release does not occur until higher serum calcium levels are attained, creating a new equilibrium.

Expert curators review the literature and organize it to facilitate your work. For all other comments, please send your remarks via contact us. Abnormal serum protein binding of calcium and magnesium in FHH was excluded. The mild and intermittent nature of hypercalcemia in heterozygotes was responsible for the earlier misinterpretation. The probands were all asymptomatic, and hypercalcemia was diagnosed at ages ranging from 21 to 53 years.

Genetic analysis of family members may also be useful.