Aromatase excess syndrome

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Aromatase excess syndrome

ORPHA:178345Disease

Also called AEXS · Familial hyperestrogenism · Hereditary prepubertal gynecomastia

What it is

A rare, genetic endocrine disease characterized by increased levels of estrogen due to elevated extraglandular aromatase activity. Males present with heterosexual precocious puberty which manifests with pre- or peripubertal onset of gynecomastia, premature growth spurt, accelerated bone maturation resulting in decreased adult stature, and may present mild hypogonadotropic hypogonadism. Female patients may have isosexual precocious puberty or not have any manifestations at all.

Key facts

Prevalence
<1 / 1 000 000
Age of onset
Adolescent, Childhood
Inheritance
Autosomal dominant
Classified as
Disease

Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.

Signs and symptoms

These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.

Gene

CYP19A1Disease-causing germline mutation(s) (gain of function)

ICD-10 codes

E30.1filed under a broader ICD-10 category — shared with 1 other rare disease

ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.

Related health topics

Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.

Cross-references

GARD 12494MESH C000591739MONDO 0007690OMIM 139300UMLS C1970109

Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.

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