MedGen

Any generalized epilepsy in which the cause of the disease is a mutation in the CASR gene. [from MONDO]

Neonatal severe hyperparathyroidism usually manifests in the first 6 months of life with severe hypercalcemia, bone demineralization, and failure to thrive. Early diagnosis is critical because untreated NSHPT can be a devastating neurodevelopmental disorder, which in some cases is lethal without parathyroidectomy. Some infants have milder hyperparathyroidism and a substantially milder clinical presentation and natural history (summary by Egbuna and Brown, 2008). [from OMIM]

Familial hypocalciuric hypercalcemia (HHC) is a heritable disorder of mineral homeostasis that is transmitted as an autosomal dominant trait with a high degree of penetrance. HHC is characterized biochemically by lifelong elevation of serum calcium concentrations and is associated with inappropriately low urinary calcium excretion and a normal or mildly elevated circulating parathyroid hormone (PTH; 168450) level. Hypermagnesemia is typically present. Individuals with HHC are usually asymptomatic and the disorder is considered benign. However, chondrocalcinosis and pancreatitis occur in some adults (summary by Hannan et al., 2010). Characteristic features of familial hypocalciuric hypercalcemia include mild to moderate hypercalcemia, nonsuppressed parathyroid hormone, relative hypocalciuria while hypercalcemic (calcium/creatinine clearance ratio less than 0.01, or 24-hr urine calcium less than 6.25 mmol), almost 100% penetrance of hypercalcemia from birth, absence of complications, persistence of hypercalcemia following subtotal parathyroidectomy, and normal parathyroid size, weight, and histology at surgery. However, atypical presentations with severe hypercalcemia, hypercalciuria with or without nephrolithiasis or nephrocalcinosis, kindreds with affected members displaying either hypercalciuria or hypocalciuria, postoperative normocalcemia, and pancreatitis have all been described in FHH (Warner et al., 2004). Genetic Heterogeneity of Hypocalciuric Hypercalcemia Familial hypocalciuric hypercalcemia type II (HHC2; 145981) is caused by mutation in the GNA11 gene (139313) on chromosome 19p13, and HHC3 (600740) is caused by mutation in the AP2S1 gene (602242) on chromosome 19q13. [from OMIM]

Autosomal dominant hypocalcemia-1 (HYPOC1) is associated with low or normal serum parathyroid hormone concentrations (PTH). Approximately 50% of patients have mild or asymptomatic hypocalcemia; about 50% have paresthesias, carpopedal spasm, and seizures; about 10% have hypercalciuria with nephrocalcinosis or kidney stones; and more than 35% have ectopic and basal ganglia calcifications (summary by Nesbit et al., 2013). Thakker (2001) noted that patients with gain-of-function mutations in the CASR gene, resulting in generally asymptomatic hypocalcemia with hypercalciuria, have low-normal serum PTH concentrations and have often been diagnosed with hypoparathyroidism because of the insensitivity of earlier PTH assays. Because treatment with vitamin D to correct the hypocalcemia in these patients causes hypercalciuria, nephrocalcinosis, and renal impairment, these patients need to be distinguished from those with other forms of hypoparathyroidism (see 146200). Thakker (2001) suggested the designation 'autosomal dominant hypocalcemic hypercalciuria' for this CASR-related disorder. Genetic Heterogeneity of Autosomal Dominant Hypocalcemia Autosomal dominant hypocalcemia-2 (HYPOC2; 615361) is caused by mutation in the GNA11 gene (139313) on chromosome 19p13. [from OMIM]