familial hypocalciuric hypercalcemia 2

Familial hypocalciuric hypercalcemia type II (FHH2) is an autosomal dominant disorder characterized by lifelong elevations of serum calcium concentrations [7][8]. This condition is marked by low urinary calcium excretion and normal circulating parathyroid hormone concentrations in most patients [9].

The genetic mechanisms underlying FHH2 are not fully understood, but it is believed to be caused by mutations in the CASR gene, similar to other forms of familial hypocalciuric hypercalcemia [12]. These mutations result in lifelong elevated calcium levels, which can have various effects on the body.

It's worth noting that FHH2 is a rare condition and more research is needed to fully understand its causes and consequences. However, it is generally considered to be a benign condition, with most patients being asymptomatic [9].

References: [7] Familial hypocalciuric hypercalcemia type II (HHC2) is an autosomal dominant disorder characterized by lifelong elevations of serum calcium concentrations. [8] Familial hypocalciuric hypercalcemia type II (HHC2) is an autosomal dominant disorder characterized by lifelong elevations of serum calcium concentrations. [9] Patients are generally asymptomatic, ... dominant disorder characterized by lifelong elevations of serum calcium concentrations with low urinary calcium excretion and normal circulating parathyroid hormone concentrations in most patients.... [12] Familial hypocalciuric hypercalcaemia is a genetic condition caused by variants in the CASR gene that results in lifelong

Familial hypocalciuric hypercalcemia type II (FHH2) is an autosomal dominant disorder characterized by lifelong elevations of serum calcium concentrations with low urinary calcium excretion and normal circulating parathyroid hormone concentrations in most patients.

Common symptoms:

• Lifelong elevated serum calcium levels
• Low urinary calcium excretion
• Normal or mildly elevated parathyroid hormone levels

Other possible symptoms:

• Fatigue [12]
• Weakness [12]
• Thought disturbances [12]

It's worth noting that many people with FHH2 do not experience any noticeable symptoms, and the condition is often diagnosed by chance during routine medical evaluations. However, if symptoms do occur, they are typically mild and may not be directly related to the elevated calcium levels.

Key points:

• FHH2 is an autosomal dominant disorder
• Characterized by lifelong elevations of serum calcium concentrations
• Low urinary calcium excretion and normal circulating parathyroid hormone concentrations in most patients
• May be asymptomatic or present with mild symptoms such as fatigue, weakness, or thought disturbances

References:

[10] Familial hypocalciuric hypercalcemia type II (HHC2) is an autosomal dominant disorder characterized by lifelong elevations of serum calcium concentrations with low urinary calcium excretion and normal circulating parathyroid hormone concentrations in most patients. [12] FHH causes lifelong hypercalcemia of varying degrees and similar to that in typical PHPT. Symptoms of FHH (e.g., fatigue, weakness, or thought disturbances) may be present but are not directly related to the elevated calcium levels.

Familial Hypocalciuric Hypercalcemia (FHH) can be diagnosed through various tests, including:

• Genetic testing: This is the most definitive test for FHH. It involves analyzing the CASR gene to detect mutations that cause the condition. Genetic testing can confirm a diagnosis of FHH and rule out other conditions that may present with similar symptoms [1][2].
• Serum calcium concentrations: Measuring serum calcium levels in family members can help identify individuals who are carriers of the mutated CASR gene. This test is often used as part of a screening process to identify potential cases of FHH [3].
• CASR mutation analysis: This test involves analyzing the CASR gene for mutations that cause FHH. It can be performed on blood or tissue samples and provides a definitive diagnosis of the condition [4].

It's worth noting that while these tests can help diagnose FHH, they may not always detect the condition in its early stages. In some cases, FHH may only become apparent during childhood, when asymptomatic hypercalcemia is detected during routine screening [5].

Treatment Options for Familial Hypocalciuric Hypercalcemia (FHH) 2

Familial hypocalciuric hypercalcemia type 2, also known as FHH 2, is a genetic condition characterized by mild hypercalcemia. While treatment is not usually necessary, as the condition is typically asymptomatic, there are some pharmacological options that can be explored.

• Calcimimetic therapy: Cinacalcet, a calcimimetic drug, has been reported to reduce symptom burden and serum calcium levels in FHH 2 [3]. This treatment option may be considered for patients with symptomatic or severe hypercalcemia.
• No response to diuretics or bisphosphonates: Unlike other causes of

Differential Diagnoses of Familial Hypocalciuric Hypercalcemia (FHH)

Familial hypocalciuric hypercalcemia (FHH) is a genetic condition characterized by mild hypercalcemia, typically found in otherwise healthy and asymptomatic individuals. When diagnosing FHH, it's essential to consider other differential diagnoses that may present with similar symptoms.

Primary Hyperparathyroidism (PHPT)

One of the most common differential diagnoses for FHH is primary hyperparathyroidism (PHPT). PHPT is a condition where one or more parathyroid glands become overactive, leading to an excess production of parathyroid hormone (PTH), which in turn causes hypercalcemia. The main differentiating factor between FHH and PHPT is the level of PTH; in FHH, PTH levels are typically normal or slightly elevated, whereas in PHPT, PTH levels are usually high.

Other Differential Diagnoses

Other differential diagnoses for FHH include:

• Humoral Malignant Hypercalcemia: A rare condition caused by a paraneoplastic syndrome associated with certain types of cancer.
• Sarcoidosis: An autoimmune disease that can cause hypercalcemia due to an excess production of vitamin D.
• Overactive Parathyroid Adenoma: A benign tumor on one of the parathyroid glands that can cause hyperparathyroidism.

Diagnostic Criteria

To differentiate FHH from other conditions, several diagnostic criteria are used:

• Calcium/Creatinine Clearance Ratio: A ratio below 0.001 is often indicative of FHH.
• Genetic Studies: Evidence of a mutation in the calcium sensor receptor gene can confirm the diagnosis of FHH.

Conclusion

In conclusion, when diagnosing familial hypocalciuric hypercalcemia (FHH), it's essential to consider other differential diagnoses that may present with similar symptoms. Primary hyperparathyroidism (PHPT) is one of the most common differential diagnoses, and can be differentiated by the level of PTH. Other conditions such as humoral malignant hypercalcemia, sarcoidosis, and overactive parathyroid adenoma should also be considered.

References:

• [1] Familial hypocalciuric hypercalcemia (FHH) is a genetic condition characterized by mild hypercalcemia, typically found in otherwise healthy and asymptomatic individuals. [10]
• Primary hyperparathyroidism (PHPT) is a condition where one or more parathyroid glands become overactive, leading to an excess production of PTH. [13]
• Other differential diagnoses for FHH include humoral malignant hypercalcemia, sarcoidosis, and overactive parathyroid adenoma. [3], [4], [5]