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Melorheostosis is a medical developmental disorder and mesenchymal dysplasia in which the bony cortex widens and becomes hyperdense in a sclerotomal distribution. The condition begins in childhood and is characterized by thickening of the bones. Pain is a frequent symptom and the bone can have the appearance of dripping candle wax.[1]

Signs and symptoms

The clinical presentation of this condition is as follows:[2]

  • Irregular bone growth
  • Cortical thickening
  • Unequal limb length
  • Soft tissue abnormalities
  • Abnormal muscles
  • Joint swelling
  • Vascular abnormalities


A randomly occurring somatic mutation of the MAP2K1 gene during fetal development is believed to be the cause.[3][4] It is not known if LEMD3 mutations can cause isolated melorheostosis in the absence of osteopoikilosis or Buschke–Ollendorff syndrome.[5]


Leg bone AP view x-ray

Melorheostosis is a mesenchymal dysplasia manifesting as regions of dripping wax appearance or flowing candle wax appearance.[6] The disorder can be detected by radiograph due to thickening of bony cortex resembling "dripping candle wax." It is included on the spectrum of developmental bone dysplasias including pycnodysostosis and osteopoikilosis.[7] The disorder tends to be unilateral and monostotic (i.e. affecting a single bone), with only one limb typically involved. Cases with involvement of multiple limbs, ribs, and bones in the spine have also been reported. There are no reported cases of involvement of skull or facial bones. Melorheostosis can be associated with pain, physical deformity, skin and circulation problems, contractures, and functional limitation. It is also associated with a benign inner ear dysplasia known as osteosclerosis.[8]


The disorder is progressive, with the ultimate severity of symptoms often depending on age of onset. In severe cases amputation has been performed when conservative measures such as physical therapy and regional anesthetics have been ineffective.[9]

See also


  1. "Definition of Melorheostosis". Archived from the original on 10 September 2017. Retrieved 9 July 2018.
  2. "Melorheostosis". NORD (National Organization for Rare Disorders). Archived from the original on 19 April 2021. Retrieved 28 December 2021.
  3. "Melorheostosis | Genetic and Rare Diseases Information Center (GARD) Archived 2020-11-11 at the Wayback Machine – an NCATS Program". Retrieved 2019-01-22.
  4. Kang H, Jha S, Deng Z, Fratzl-Zelman N, Cabral WA, Ivovic A, Meylan F, Hanson EP, Lange E, Katz J, Roschger P, Klaushofer K, Cowen EW, Siegel RM, Marini JC, Bhattacharyya T (April 2018). "Somatic activating mutations in MAP2K1 cause melorheostosis". Nature Communications. 9 (1): 1390. Bibcode:2018NatCo...9.1390K. doi:10.1038/s41467-018-03720-z. PMC 5895796. PMID 29643386.
  5. Zhang Y, Castori M, Ferranti G, Paradisi M, Wordsworth BP (June 2009). "Novel and recurrent germline LEMD3 mutations causing Buschke-Ollendorff syndrome and osteopoikilosis but not isolated melorheostosis". Clinical Genetics. 75 (6): 556–61. doi:10.1111/j.1399-0004.2009.01177.x. PMID 19438932.
  6. Salam, Hani. "Melorheostosis - Radiology Reference Article -". Archived from the original on 10 July 2018. Retrieved 9 July 2018.
  7. Azouz ME, Greenspan A. "Melorheostosis -" (PDF). Archived (PDF) from the original on 2016-08-16. Retrieved 2020-11-05.
  8. Subhas N, Sundaram M, Bauer TW, Seitz WH, Recht MP (February 2008). "Glenoid labrum ossification and mechanical restriction of joint motion: extraosseous manifestations of melorheostosis". Skeletal Radiology. 37 (2): 177–81. doi:10.1007/s00256-007-0405-4. PMID 18030463. Archived from the original on 2022-01-11. Retrieved 2020-11-05.
  9. Graham LE, Parke RC (April 2005). "Melorheostosis--an unusual cause of amputation". Prosthetics and Orthotics International. 29 (1): 83–6. doi:10.1080/17461550500066808. PMID 16180380. Archived from the original on 2022-01-11. Retrieved 2020-11-05.

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