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Disease Profile

Morgagni-Stewart-Morel syndrome

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.


US Estimated

Europe Estimated

Age of onset






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


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.


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.


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


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.


Not applicable


Other names (AKA)

MSM syndrome; Hyperostosis frontalis interna, obesity, shortness and cognitive impairment


Congenital and Genetic Diseases


Morgagni-Stewart-Morel (MSM) syndrome is a disorder characterized by thickening of the frontal bone of the skull (hyperostosis frontalis interna), as well as obesity and excessive hair growth (hypertrichosis).[1] Other signs and symptoms may include seizures, headaches, diabetes insipidus, and sex gland disturbances.[2] The cause of Morgagni-Stewart-Morel syndrome is not fully understood. Some instances of dominant inheritance have been reported, but whether it is autosomal dominant or X-linked dominant is not known.[3] Treatment may include medication for headaches and seizures and surgery to remove the excessive bone of the skull.[2][4]


Morgagni-Stewart-Morel (MSM) syndrome typically include a characteristic X-ray finding of thickening of the frontal bone of the skull (hyperostosis frontalis interna). The signs and symptoms of MSM commonly include:[2][3][5]

Some people may also have the following signs and symptoms:[2][3][5] 

  • Depression
  • Irritability
  • Fatigue
  • Temporary paralysis on one side of the body
  • Hearing impairment
  • Paralysis of the cranial nerves
  • Muscle weakness
  • Seizures

While people with Morgagni-Stewart-Morel syndrome nearly always have hyperostosis frontalis interna, hyperostosis frontalis interna is usually an incidental finding on x-ray films, computed tomography, or magnetic resonance imaging of the head and by itself is not indicative of any disease.[6]

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
Percent of people who have these symptoms is not available through HPO
Autosomal dominant inheritance
Diabetes mellitus
Elevated alkaline phosphatase
Greatly elevated alkaline phosphatase
High serum alkaline phosphatase
Increased alkaline phosphatase
Increased serum alkaline phosphatase

[ more ]

Spontaneous milk flow from breast
Hyperostosis frontalis interna
Increased circulating prolactin concentration
Irregular menstruation
Menstrual irregularity
Having too much body fat


The cause of Morgagni-Stewart-Morel syndrome and hyperostosis frontalis interna is unknown, although some have suggested that a hormonal imbalance due to genetic and environmental factors may be the cause of many of the symptoms of the syndrome.[3]


The diagnosis of Morgagni-Stewart-Morel syndrome is based upon a radiological finding of hyperostosis frontalis interna, as well as a combination of clinical features including obesity, virulism (a female disorder in which there is development of secondary male sexual characteristics like growth of facial and body hair), possible mental disturbance, and other findings.[3][6]


Currently, there is no cure or specific recommendations for the treatment of this syndrome. Treatment depends on the symptoms present, and may include medication and diet and lifestyle modification for weight control. Diabetes and hypertension are treated with standard medication.[7] 

Seizures and headaches that may be associated with hyperostosis frontalis interna (HFI) are typically treated with standard medications.[2]

In one journal article, the authors discuss a person with Morgagni-Stewart-Morel syndrome who reportedly had violent headaches. Surgery was performed to remove the hypertrophic frontal bone on the patient. He then had dura and bone reconstruction. The authors reported that the headaches stopped immediately after the operation. [4]

Another article described a patient with HFI and intracranial hypertension (increased pressure inside the skull and brain). The authors reported good results with a craniotomy (a surgical operation in which a bone flap is temporarily removed from the skull to access the brain) performed to decrease the intracranial pressure.[8]


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

    • 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

      • MeSH® (Medical Subject Headings) is a terminology tool used by the National Library of Medicine. Click on the link to view information on this topic.
      • 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.
      • 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. 
      • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
      • PubMed is a searchable database of medical literature and lists journal articles that discuss Morgagni-Stewart-Morel syndrome. Click on the link to view a sample search on this topic.


        1. Morgagni-Stewart-Morel syndrome. Orphanet. June 2006; https://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=77296.
        2. Hyperostosis Frontalis Interna. NORD. 2007; https://rarediseases.org/rare-diseases/hyperostosis-frontalis-interna/.
        3. Hyperostosis frontalis interna. OMIM. 2016; https://omim.org/entry/144800.
        4. Latka D, Szydlik W, Glaubic-Latka M & Mrówka R. [A case of Morgagni-Morel-Stewart syndrome with violent headaches predominant in the clinical course treated surgically]. Neurologia Neurochirurgia Polska. March-April 1995; 29(2):253-256. https://www.ncbi.nlm.nih.gov/pubmed/7651598.
        5. Nallegowda M, Singh U, Khanna M, Yadav SL, Choudhary AR &Thakar A. Morgagni Stewart morel syndrome-Additional features. Neurology India. 2005; https://www.ncbi.nlm.nih.gov/pubmed/15805672.
        6. Waclawik AJ. Hyperostosis frontalis interna. Arch Neurol. 2006; https://www.ncbi.nlm.nih.gov/pubmed/16476822.
        7. Gracia-Ramos AE. Morgagni-Stewart-Morel syndrome. Case report and review of the literature.. Rev Med Inst Mex Seg Soc. 2016; 54(5):664-9. https://www.ncbi.nlm.nih.gov/pubmed/27428347.
        8. Elliott C, Johnson E & Chow M. Hyperostosis frontalis interna requiring craniotomy for intracranial hypertension. Can J Neurol Sci.. January, 2014; 41(1):109-11. https://www.ncbi.nlm.nih.gov/pubmed/24384350.

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