Aromatase excess syndrome
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Reviewed April 2014
What is aromatase excess syndrome?
Aromatase excess syndrome is a condition characterized by elevated levels of the female sex hormone estrogen in both males and females. Males with aromatase excess syndrome experience breast enlargement (gynecomastia) in late childhood or adolescence. The bones of affected males grow and develop more quickly and stop growing sooner than usual (advanced bone age). As a result males have an early growth spurt, typically during late childhood, with short stature as an adult. Affected females rarely show signs and symptoms of the condition, but they may have increased breast growth (macromastia), irregular menstrual periods, and short stature. The ability to have children (fertility) is usually normal in both males and females with aromatase excess syndrome.
How common is aromatase excess syndrome?
The prevalence of aromatase excess syndrome is unknown; more than 20 cases have been described in the medical literature.
What genes are related to aromatase excess syndrome?
Rearrangements of genetic material involving the CYP19A1 gene cause aromatase excess syndrome. TheCYP19A1 gene provides instructions for making an enzyme called aromatase. This enzyme converts a class of hormones called androgens, which are involved in male sexual development, to different forms of estrogen. In females, estrogen guides female sexual development before birth and during puberty. In both males and females, estrogen plays a role in regulating bone growth.
The condition can result from several types of genetic rearrangements involving the CYP19A1 gene. These rearrangements alter the activity of the gene and lead to an increase in aromatase production. In affected males, the increased aromatase and subsequent conversion of androgens to estrogen are responsible for the gynecomastia and limited bone growth characteristic of aromatase excess syndrome. Increased estrogen in females can cause symptoms such as irregular menstrual periods and short stature.
Read more about the CYP19A1 gene.
How do people inherit aromatase excess syndrome?
This condition is inherited in an autosomal dominant pattern, which means a genetic rearrangement involving one copy of the CYP19A1 gene in each cell is sufficient to cause the disorder.
In some cases, an affected person inherits the mutation from one affected parent. Other cases result from new genetic changes and occur in people with no history of the disorder in their family.
Where can I find information about diagnosis or management of aromatase excess syndrome?
These resources address the diagnosis or management of aromatase excess syndrome and may include treatment providers.
- Genetic Testing Registry: Familial gynecomastia, due to increased aromatase
- Lab Tests Online:
You might also find information on the diagnosis or management of aromatase excess syndrome inEducational resources and Patient support.
General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.
Where can I find additional information about aromatase excess syndrome?
You may find the following resources about aromatase excess syndrome helpful. These materials are written for the general public.
You may also be interested in these resources, which are designed for healthcare professionals and researchers.
What other names do people use for aromatase excess syndrome?
- familial gynecomastia due to increased aromatase activity
- hereditary gynecomastia
- increased aromatase activity
What if I still have specific questions about aromatase excess syndrome?
Where can I find general information about genetic conditions?
The Handbook provides basic information about genetics in clear language.
- What does it mean if a disorder seems to run in my family?
- What are the different ways in which a genetic condition can be inherited?
- If a genetic disorder runs in my family, what are the chances that my children will have the condition?
- Why are some genetic conditions more common in particular ethnic groups?
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding aromatase excess syndrome?
androgens ; autosomal ; autosomal dominant ; cell ; class ; enzyme ; familial ; fertility ; gene ;gynecomastia ; hormone ; mutation ; prevalence ; puberty ; rearrangement ; sex hormone ; short stature ;stature ; syndrome
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (4 links)
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.