Rare Endocrinology News

Disease Profile

Pseudohypoparathyroidism

Prevalence
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.
1-9 / 1 000 000

331 - 2,979

US Estimated

1-9 / 1 000 000

514 - 4,622

Europe Estimated

Age of onset

All ages

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ICD-10

E20.1

Inheritance

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease

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Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype

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X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

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X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder

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Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

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Not applicable

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Categories

Endocrine Diseases

Summary

Pseudohypoparathyroidism is a genetic disorder in which the body is unable to respond to parathyroid hormone. Parathyroid hormone helps control calcium, phosphorous, and vitamin D levels in the bones and blood. Hypoparathyroidism is a similar condition in which the body does not make enough parathyroid hormone instead of not being able to respond to it (as in pseudohypoparathyroidism).[1]

The symptoms of these two conditions are similar and are caused by low calcium levels and high phosphate levels in the blood. This may cause cataracts (clouding of the lens of the eye), dental problems, numbness, seizures, or tetany (muscle twitches and hand and foot spasms). These symptoms are usually first seen in childhood.[1]

There are two different types of pseudohypoparathyroidism, both of which are caused by spelling mistakes (mutations) in certain genes. Type 1 can be further divided into three sub-types.[1] Click on the links below for more information on the various types of pseudohypoparathyroidism.

Pseudohypoparathyroidism type 1A
Pseudohypoparathyroidism type 1B
Pseudohypoparathyroidism type 1C
Pseudohypoparathyroidism type 2

Cause

Pseudohypoparathyroidism is caused by changes (mutations) in a number of different genes including the GNAS1 gene. When this gene is not working correctly, the body is not able to properly respond to parathyroid hormone, which increases the level of phosphorous in the blood and decreases the level of calcium. A mutation in this gene is most often inherited from the affected person’s mother, although it can sometimes be inherited from the father.[2]

Diagnosis

Pseudohypoparathyroidism can be diagnosed by blood or urine tests to measure the levels of calcium, phosphorous, and parathyroid hormone. If the levels of parathyroid hormone and phosphorous are high and if the levels of calcium or low, this indicates the possibility of pseudohypoparathyroidism. A doctor may wish to confirm the diagnosis through genetic testing for a mutation in the GNAS1 gene.[3]

Treatment

The goal of treatment for pseudohypoparathyroidism is to return the levels of calcium and phosphorous to normal. This can be done by taking calcium supplements to increase the level of calcium in the body. Vitamin D supplements also indirectly work to increase calcium levels in the body because vitamin D improves the absorption of calcium.[3] The doctors may also recommend a low-phosphate diet or specific medications that bind to phosphate in the blood and reduce the effects.

Because people affected with certain types of pseudohypoparathyroidism may be shorter than other people, growth hormone may also be a treatment that allows these individuals to grow taller than they otherwise would.[4]

Organizations

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

    Learn more

    These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

    Where to Start

    • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
    • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

      In-Depth Information

      • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
      • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
      • The Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
      • PubMed is a searchable database of medical literature and lists journal articles that discuss Pseudohypoparathyroidism. Click on the link to view a sample search on this topic.

        Selected Full-Text Journal Articles

          References

          1. Topiwala S. Pseudohypoparathyroidism. MedlinePlus. July 2012; https://www.nlm.nih.gov/medlineplus/ency/article/000364.htm. Accessed 10/17/2012.
          2. Garin I, Mantovani G, Aguirre U, Barlier A, Brix B, Elli FM, Freson K, Grybek V, Izzi B, Linglart A, Perez de Nanclares G, Silve C, Thiele S, and Werner R. European guidance for the molecular diagnosis of pseudohypoparathyroidism not caused by point genetic variants at GNAS: an EQA study. European Journal of Human Genetics. April 2015; 23(4):438-444. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4666570/.
          3. Abraham MR and Khardori R. Pseudohypoparathyroidism. Medscape; December 11, 2015; https://emedicine.medscape.com/article/124836-overview.
          4. Germain-Lee EL. Short stature, obesity, and growth hormone deficiency in pseudohypoparathyroidism type 1a. Pediatric Endocrinology Reviews. April 2006; 3:318-327. https://www.ncbi.nlm.nih.gov/pubmed/16675931.

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