Sandbox:Mazia

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mazia Fatima, MBBS [2]

Overview

Pseudohypoparathyroidism (PHP) refers to a group of rare endocrine disorders characterized by end organ resistance to the action of parathyroid hormone (PTH), manifestations include hypocalcemia, hyperphosphatemia, and increased serum concentration of PTH.

Historical Perspective

In 1942, Fuller albright, an American endocrinologist, first discovered pseudohypoparathyroidim. Pseudohypoparathyoroidism is the first hormone resistance syndrome to be discovered.

Classification

• Pseudohypoparathyroidism is classified based on the measurement of serum and urinary cAMP and phosphate excretion levels after the injection of biologically active PTH into following types:
  • Pseudohypoparathyroidism type I
  • Pseudohypoparathyroidism type II

• Pseudohypoparathyroidism type 1 is further classified into following subtype:
  • Pseudohypoparathyroidism type 1a
  • Pseudohypoparathyroidism type 1b
  • Pseudohypoparathyroidism type 1c subtypes.
  • Pseudopseudohypoparathyroidism

Pathophysiology

Pseudohypoparathyroidism is characterized by end organ resistance to Parathyroid hormone. Parathyroid hormone effect is mediated by the parathyroid hormone receptor type 1, which acts on a stimulatory guanine-nucleotide–binding (Gs) protein, which is composed of three subunits (α, β, and γ). The GNAS1 gene encodes Gsα subunit that mediates cyclic AMP stimulation by parathyroid hormone and by several other peptide hormones, including thyrotropin. Gene mutation results in failure of signal transduction through Gsα inability to activate adenyl cyclase resulting in resistance of target tissues to parathyroid hormone evidenced by hypocalcemia and hyperphosphatemia, in the presence of high plasma PTH level.

Genetics

Type of pseudohyoparathyroidism		Molecular Defect	Origin Of Mutation	Inheritence
Pseudohypoparathyroidism type I	Type 1a	Heterozygous GNAS inactivating mutations that reduce expression or function of Gαs	Maternal	Autosomal Dominant trait
	Type 1b	Familial-Heterozygous deletions in STX16, NESP55, and/or AS exons. Loss of methylation at GNAS	Maternal	Autosomal Dominant trait
		Sporadic-Paternal Uniparental disomy of chromosome 20q in some;Methylation defect affecting all four GNAS DMRs	Maternal	Genomic imprinting
	Type 1c	Heterozygous GNAS inactivating mutations that reduce expression or function of Gαs	Maternal	Autosomal Dominant trait
Pseudopseudohypoparathyroidism		Combination of inactivating mutations of GNAS1 and Albright's osteodystrophy	Paternal	Genomic imprinting
Pseudohypoparathyroidism type II		Insufficient data to suggest genetic or familial source	N/A	N/A

Causes

Disease name] may be caused by [cause1], [cause2], or [cause3].

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Common causes of [disease] include [cause1], [cause2], and [cause3].

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The most common cause of [disease name] is [cause 1]. Less common causes of [disease name] include [cause 2], [cause 3], and [cause 4].

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The cause of [disease name] has not been identified. To review risk factors for the development of [disease name], click here.

Differentiating ((Page name)) from Other Diseases

[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as [differential dx1], [differential dx2], and [differential dx3].

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[Disease name] must be differentiated from [[differential dx1], [differential dx2], and [differential dx3].

Epidemiology and Demographics

The incidence/prevalence of [disease name] is approximately [number range] per 100,000 individuals worldwide.

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In [year], the incidence/prevalence of [disease name] was estimated to be [number range] cases per 100,000 individuals worldwide.

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In [year], the incidence of [disease name] is approximately [number range] per 100,000 individuals with a case-fatality rate of [number range]%.

Patients of all age groups may develop [disease name].

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The incidence of [disease name] increases with age; the median age at diagnosis is [#] years.

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[Disease name] commonly affects individuals younger than/older than [number of years] years of age.

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[Chronic disease name] is usually first diagnosed among [age group].

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[Acute disease name] commonly affects [age group].

There is no racial predilection to [disease name].

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[Disease name] usually affects individuals of the [race 1] race. [Race 2] individuals are less likely to develop [disease name].

[Disease name] affects men and women equally.

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[Gender 1] are more commonly affected by [disease name] than [gender 2]. The [gender 1] to [gender 2] ratio is approximately [number > 1] to 1.

The majority of [disease name] cases are reported in [geographical region].

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[Disease name] is a common/rare disease that tends to affect [patient population 1] and [patient population 2].

Risk Factors

There are no established risk factors for [disease name].

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The most potent risk factor in the development of [disease name] is [risk factor 1]. Other risk factors include [risk factor 2], [risk factor 3], and [risk factor 4].

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Common risk factors in the development of [disease name] include [risk factor 1], [risk factor 2], [risk factor 3], and [risk factor 4].

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Common risk factors in the development of [disease name] may be occupational, environmental, genetic, and viral.

Screening

There is insufficient evidence to recommend routine screening for [disease/malignancy].

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According to the [guideline name], screening for [disease name] is not recommended.

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According to the [guideline name], screening for [disease name] by [test 1] is recommended every [duration] among patients with [condition 1], [condition 2], and [condition 3].

Natural History, Complications, and Prognosis

If left untreated, [#]% of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].

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Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].

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Prognosis is generally excellent/good/poor, and the 1/5/10-year mortality/survival rate of patients with [disease name] is approximately [#]%.

Diagnosis

Diagnostic Criteria

The diagnosis of [disease name] is made when at least [number] of the following [number] diagnostic criteria are met: [criterion 1], [criterion 2], [criterion 3], and [criterion 4].

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The diagnosis of [disease name] is based on the [criteria name] criteria, which include [criterion 1], [criterion 2], and [criterion 3].

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The diagnosis of [disease name] is based on the [definition name] definition, which includes [criterion 1], [criterion 2], and [criterion 3].

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There are no established criteria for the diagnosis of [disease name].

History and Symptoms

The majority of patients with [disease name] are asymptomatic.

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The hallmark of [disease name] is [finding]. A positive history of [finding 1] and [finding 2] is suggestive of [disease name]. The most common symptoms of [disease name] include [symptom 1], [symptom 2], and [symptom 3]. Common symptoms of [disease] include [symptom 1], [symptom 2], and [symptom 3]. Less common symptoms of [disease name] include [symptom 1], [symptom 2], and [symptom 3].

Physical Examination

Patients with [disease name] usually appear [general appearance]. Physical examination of patients with [disease name] is usually remarkable for [finding 1], [finding 2], and [finding 3].

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Common physical examination findings of [disease name] include [finding 1], [finding 2], and [finding 3].

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The presence of [finding(s)] on physical examination is diagnostic of [disease name].

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The presence of [finding(s)] on physical examination is highly suggestive of [disease name].

Laboratory Findings

An elevated/reduced concentration of serum/blood/urinary/CSF/other [lab test] is diagnostic of [disease name].

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Laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

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[Test] is usually normal among patients with [disease name].

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Some patients with [disease name] may have elevated/reduced concentration of [test], which is usually suggestive of [progression/complication].

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There are no diagnostic laboratory findings associated with [disease name].

Electrocardiogram

There are no ECG findings associated with [disease name].

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An ECG may be helpful in the diagnosis of [disease name]. Findings on an ECG suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

X-ray

There are no x-ray findings associated with [disease name].

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An x-ray may be helpful in the diagnosis of [disease name]. Findings on an x-ray suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

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There are no x-ray findings associated with [disease name]. However, an x-ray may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].

Echocardiography or Ultrasound

There are no echocardiography/ultrasound findings associated with [disease name].

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Echocardiography/ultrasound may be helpful in the diagnosis of [disease name]. Findings on an echocardiography/ultrasound suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

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There are no echocardiography/ultrasound findings associated with [disease name]. However, an echocardiography/ultrasound may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].

CT scan

There are no CT scan findings associated with [disease name].

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[Location] CT scan may be helpful in the diagnosis of [disease name]. Findings on CT scan suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

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There are no CT scan findings associated with [disease name]. However, a CT scan may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].

MRI

There are no MRI findings associated with [disease name].

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[Location] MRI may be helpful in the diagnosis of [disease name]. Findings on MRI suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

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There are no MRI findings associated with [disease name]. However, a MRI may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].

Other Imaging Findings

There are no other imaging findings associated with [disease name].

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[Imaging modality] may be helpful in the diagnosis of [disease name]. Findings on an [imaging modality] suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

Other Diagnostic Studies

There are no other diagnostic studies associated with [disease name].

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[Diagnostic study] may be helpful in the diagnosis of [disease name]. Findings suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].

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Other diagnostic studies for [disease name] include [diagnostic study 1], which demonstrates [finding 1], [finding 2], and [finding 3], and [diagnostic study 2], which demonstrates [finding 1], [finding 2], and [finding 3].

Treatment

Medical Therapy

There is no treatment for [disease name]; the mainstay of therapy is supportive care.

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Supportive therapy for [disease name] includes [therapy 1], [therapy 2], and [therapy 3].

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The majority of cases of [disease name] are self-limited and require only supportive care.

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[Disease name] is a medical emergency and requires prompt treatment.

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The mainstay of treatment for [disease name] is [therapy].

OR   The optimal therapy for [malignancy name] depends on the stage at diagnosis.

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[Therapy] is recommended among all patients who develop [disease name].

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Pharmacologic medical therapy is recommended among patients with [disease subclass 1], [disease subclass 2], and [disease subclass 3].

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Pharmacologic medical therapies for [disease name] include (either) [therapy 1], [therapy 2], and/or [therapy 3].

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Empiric therapy for [disease name] depends on [disease factor 1] and [disease factor 2].

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Patients with [disease subclass 1] are treated with [therapy 1], whereas patients with [disease subclass 2] are treated with [therapy 2].

Surgery

Surgical intervention is not recommended for the management of [disease name].

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Surgery is not the first-line treatment option for patients with [disease name]. Surgery is usually reserved for patients with either [indication 1], [indication 2], and [indication 3]

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The mainstay of treatment for [disease name] is medical therapy. Surgery is usually reserved for patients with either [indication 1], [indication 2], and/or [indication 3].

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The feasibility of surgery depends on the stage of [malignancy] at diagnosis.

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Surgery is the mainstay of treatment for [disease or malignancy].

Primary Prevention

There are no established measures for the primary prevention of [disease name].

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There are no available vaccines against [disease name].

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Effective measures for the primary prevention of [disease name] include [measure1], [measure2], and [measure3].

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[Vaccine name] vaccine is recommended for [patient population] to prevent [disease name]. Other primary prevention strategies include [strategy 1], [strategy 2], and [strategy 3].

Secondary Prevention

There are no established measures for the secondary prevention of [disease name].

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Effective measures for the secondary prevention of [disease name] include [strategy 1], [strategy 2], and [strategy 3].

References

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