Muscular phosphorylase kinase deficiency
Definition[edit | edit source]
Glycogen storage disease due to muscle phosphorylase kinase (PhK) deficiency is a benign inborn error of glycogen metabolism characterized by exercise intolerance.
Epidemiology[edit | edit source]
The disease is very rare with less than 30 patients reported in the literature.
Genetics[edit | edit source]
- Phosphorylase kinase (PhK) is an enzyme which plays a key role in the regulation of glycogenolysis as it is required for glycogen phosphorylase activation.
- It consists of four copies of each four subunits (alpha, beta, gamma and calmoduline) encoded by different genes on different chromosomes and differentially expressed in various tissues.
- Muscle-specific isoforms of the alpha and gamma subunits are encoded by the PHKA1 gene and the PHKG1 gene respectively, but until now mutations have been only identified in the PHKA1 gene and the transmission is X-linked.
Onset[edit | edit source]
The disease starts generally in adolescence or adulthood.
Signs and symptoms[edit | edit source]
- Patients may present with exercise intolerance with myalgia, cramps, fatigue, and sometimes myoglobinuria. In some cases, patients may present with progressive muscle weakness.
- Symptoms are usually mild, and myopathy may be asymptomatic.
- A neonatal form with generalized muscular hypotonia and respiratory insufficiency has also been described.
Diagnosis[edit | edit source]
Biochemical diagnosis of the muscle form can be made by measuring phosphorylase kinase activity in a muscle biopsy. Genetic testing is useful to confirm or establish the diagnosis.
Differential diagnosis Differential diagnoses include GSD due to myophosphorylase deficiency (GSD type V), and other GSDs affecting the muscle (GSD types XI, XII, XIII and XIV).
Treatment[edit | edit source]
Most patients do not require any specific treatment.
Prognosis[edit | edit source]
Prognosis is good.
NIH genetic and rare disease info[edit source]
Muscular phosphorylase kinase deficiency is a rare disease.
| This article is a stub. You can help WikiMD by registering to expand it. |
Search WikiMD
Ad.Tired of being Overweight? Try W8MD's physician weight loss program.
Semaglutide (Ozempic / Wegovy and Tirzepatide (Mounjaro / Zepbound) available.
Advertise on WikiMD
|
WikiMD's Wellness Encyclopedia |
| Let Food Be Thy Medicine Medicine Thy Food - Hippocrates |
Translate this page: - East Asian
中文,
日本,
한국어,
South Asian
हिन्दी,
தமிழ்,
తెలుగు,
Urdu,
ಕನ್ನಡ,
Southeast Asian
Indonesian,
Vietnamese,
Thai,
မြန်မာဘာသာ,
বাংলা
European
español,
Deutsch,
français,
Greek,
português do Brasil,
polski,
română,
русский,
Nederlands,
norsk,
svenska,
suomi,
Italian
Middle Eastern & African
عربى,
Turkish,
Persian,
Hebrew,
Afrikaans,
isiZulu,
Kiswahili,
Other
Bulgarian,
Hungarian,
Czech,
Swedish,
മലയാളം,
मराठी,
ਪੰਜਾਬੀ,
ગુજરાતી,
Portuguese,
Ukrainian
Medical Disclaimer: WikiMD is not a substitute for professional medical advice. The information on WikiMD is provided as an information resource only, may be incorrect, outdated or misleading, and is not to be used or relied on for any diagnostic or treatment purposes. Please consult your health care provider before making any healthcare decisions or for guidance about a specific medical condition. WikiMD expressly disclaims responsibility, and shall have no liability, for any damages, loss, injury, or liability whatsoever suffered as a result of your reliance on the information contained in this site. By visiting this site you agree to the foregoing terms and conditions, which may from time to time be changed or supplemented by WikiMD. If you do not agree to the foregoing terms and conditions, you should not enter or use this site. See full disclaimer.
Credits:Most images are courtesy of Wikimedia commons, and templates, categories Wikipedia, licensed under CC BY SA or similar.
Contributors: Deepika vegiraju
