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Disease Profile

Hunter-McAlpine 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.

<1 / 1 000 000

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)

Hunter-mcalpine craniosynostosis syndrome; Hunter-mcalpine craniosynostosis; Craniosynostosis, mental deficiency, almond-shaped palpebral fissures, downturned mouth, mild acral-skeletal anomalies, and short stature


Congenital and Genetic Diseases; Musculoskeletal Diseases


Hunter-McAlpine syndrome is a very rare condition characterized by developmental delay, intellectual disability, and small head size (microcephaly). Sometimes the microcephaly results from early closure of the bones in the skull, which is called craniosynostosis. This can cause a misshapen skull and is common in individuals with Hunter-McAlpine syndrome; in fact another name for the condition is Hunter-McAlpine craniosynostosis syndrome.[1] Hunter-McAlpine syndrome is a genetic condition, meaning that it is caused by changes in the genes. Hunter-McAlpine syndrome is typically diagnosed by genetic testing, and treatment options are focused on managing each individual’s symptoms. 


The symptoms of Hunter-McAlpine syndrome include characteristic facial features such as almond-shaped eyes, drooping lower eyelids (ptosis), and a small down-turned mouth. These characteristic facial features cause many children with Hunter-McAlpine syndrome to look like each other. Other symptoms of Hunter-McAlpine syndrome include intellectual disability, developmental delay, microcephaly, and short stature.[2] Although there is some variability, some children affected by the condition may have delayed puberty or heart defects.[3] Some affected individuals may also have skeletal changes that affect their fingers and toes. 

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
Almond-shaped palpebral fissure
Almond shaped eyes
Almond-shaped opening between the eyelids

[ more ]

Autosomal dominant inheritance
Downturned corners of mouth
Downturned corners of the mouth
Downturned mouth

[ more ]

Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific

[ more ]

Narrow mouth
Small mouth
Short stature
Decreased body height
Small stature

[ more ]



Hunter-McAlpine syndrome is a genetic condition, meaning that it is caused by changes in a person’s genes. Each cell in our bodies contains 23 pairs of chromosomes for a total of 46 chromosomes in each cell. These chromosomes are packets of genetic information. People affected by Hunter-McAlpine syndrome have a duplication of part of chromosome 5.[1] This duplication results in extra genetic information and causes the symptoms associated with Hunter-McAlpine syndrome.


Hunter-McAlpine syndrome is diagnosed by a clinical evaluation and genetic testing. If the genetic test shows that there is a duplication of a specific part of chromosome 5, this confirms the diagnosis of Hunter-McAlpine syndrome.[1] The doctor may also suggest testing other members of the family. Any siblings might be tested to see if they are affected as well, and parents might be tested to better understand the chance that any future children may be affected with the condition.

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.

In-Depth Information

  • 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 Hunter-McAlpine syndrome. Click on the link to view a sample search on this topic.


  1. Hunter-McAlpine craniosynostosis. Orphanet; September 2007; https://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=97340.
  2. Hunter AG, Dupont B, McLaughlin M, Hinton L, Baker E, Adés L, Haan E, and Schwartz CE. The Hunter-McAlpine syndrome results from duplication 5q35-5qter. Clinical Genetics. January 2005; 67(1):53-60. https://www.ncbi.nlm.nih.gov/pubmed/15617549.
  3. Adés LC, Morris LL, Simpson DA, Haan EA. Hunter-McAlpine syndrome: report of a third family. Clinical Dysmorphology. April 1993; 2(2):123-130. https://www.ncbi.nlm.nih.gov/pubmed/8281273.
  4. O’Neill MJF and McKusick VA. Hunter-McAlpine Craniosynostosis Syndrome. Online Mendelian Inheritance in Man; September 19, 2016; https://www.omim.org/entry/601379.

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