What you carry at this position in your DNA and what research says about it.
Height and Development: 10/10 evidence, 31 publications.
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Sample genotype (not yours): C/C
Taller Stature and Lower Fibroid Risk
Two copies of the C allele are linked to taller adult height and a lower risk of developing uterine fibroids.
What this genotype means: Taller adult stature; Lower risk of uterine fibroids; Larger cerebral cortex surface area.
Sample genotype (not yours): A/A
Shorter Stature and Higher Fibroid Risk
Two copies of the A allele are linked to shorter adult height and an increased risk of uterine fibroids.
What this genotype means: Shorter adult stature; Increased risk of uterine fibroids; Smaller cerebral cortex surface area.
Sample genotype (not yours): C/A
Typical Height and Average Fibroid Risk
Carrying one C and one A allele is associated with average adult height and typical health risks.
What this genotype means: Average adult height; Typical risk of uterine fibroids; Average cerebral cortex surface area.
Gene function and biological role
Gene Function: The HMGA2 gene encodes an architectural transcription factor that plays a critical role in embryonic development, cell growth, and tissue differentiation. It is highly active during fetal development, where it coordinates the rapid proliferation of mesenchymal cells, but remains nearly silent in most adult tissues. Variations in this gene are among the most well-replicated genetic determinants of natural human height and skeletal frame size [1]. Because of its role in driving cell division, abnormal reactivation of HMGA2 in adult tissues is frequently linked to the formation of benign tumors, such as uterine fibroids [2].
Variant Impact: The rs8756 variant is located in the 3 prime untranslated region of the HMGA2 gene, a regulatory region that controls gene stability and translation. This specific nucleotide change is thought to alter the binding affinity of microRNAs, thereby influencing how much HMGA2 protein is produced [3]. The C allele is associated with higher expression levels, promoting skeletal growth and resulting in taller stature [1]. Conversely, the A allele is linked to reduced expression, which is associated with shorter stature and an increased susceptibility to benign uterine tumors [2].
Key Insight: A single genetic spelling change in HMGA2 simultaneously influences adult height, the surface area of the brain's cerebral cortex, and the risk of developing uterine fibroids.
Location: HMGA2. Chromosome 12 · 12q14.3 · 66.0 Mb
Estimated prevalence by population
Global 19.1%; European 23.9%; African 16.5%; East Asian 1.0%; South Asian 6.2%; Americas 13.9%; Ashkenazi 10.6%; Finnish 24.6%; Middle Eastern 14.3%; Amish 21.9%.
Estimated CC genotype frequency.
Global 47.5%; European 50.0%; African 48.2%; East Asian 18.1%; South Asian 37.3%; Americas 46.7%; Ashkenazi 43.9%; Finnish 50.0%; Middle Eastern 47.0%; Amish 49.8%.
Estimated CA genotype frequency.
Global 33.3%; European 26.2%; African 35.2%; East Asian 80.9%; South Asian 56.5%; Americas 39.4%; Ashkenazi 45.5%; Finnish 25.4%; Middle Eastern 38.7%; Amish 28.3%.
Estimated AA genotype frequency.
Showing effects for C/C genotype
Lifestyle, Fitness & Aging
Height & Body Size
Height. Evidence: 10/10. Source: PMID 18391951. Taller Stature.
Endocrine & Reproductive
Female Reproductive Health & Fertility
Uterine Fibroids. Evidence: 3/10. Source: PMID 19132395. Lower Risk.
Pregnancy & Birth Complications
Birth Weight. Evidence: 7/10. Source: PMID 31043758. Higher Birth Weight.
Neurology & Mental Health
Neurodevelopmental Traits
Cerebral Cortex Area. Evidence: 8/10. Source: PMID 34910505. Larger Surface Area.
Showing effects for A/A genotype
Height. Evidence: 10/10. Source: PMID 18391951. Shorter Stature.
Uterine Fibroids. Evidence: 3/10. Source: PMID 19132395. Increased Risk.
Birth Weight. Evidence: 7/10. Source: PMID 31043758. Lower Birth Weight.
Cerebral Cortex Area. Evidence: 8/10. Source: PMID 34910505. Smaller Surface Area.
Showing effects for C/A genotype
Height. Evidence: 10/10. Source: PMID 18391951. Typical Height.
Uterine Fibroids. Evidence: 3/10. Source: PMID 19132395. Typical Risk.
Birth Weight. Evidence: 7/10. Source: PMID 31043758. Typical.
Cerebral Cortex Area. Evidence: 8/10. Source: PMID 34910505. Typical Area.
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Carrying two copies of the C allele is consistently associated with an increase in adult height, with studies showing a cumulative effect on skeletal growth [1]. This genetic variant influences the expression of HMGA2, a key regulator of cell proliferation during development [2]. In addition to taller stature, this genotype is linked to a larger surface area of the cerebral cortex in the brain [3]. Importantly, the C allele appears to be protective against the development of uterine leiomyomata, commonly known as uterine fibroids [4]. Individuals with this genotype also tend to have slightly higher birth weights, reflecting the gene's role in early fetal growth [5].
Taller adult stature; Lower risk of uterine fibroids; Larger cerebral cortex surface area.
Sample genotype: AA (Homozygous)
Carrying two copies of the A allele is associated with a reduction in adult height, as this genotype is linked to lower expression of the HMGA2 growth regulator [1]. This lower expression level influences skeletal development, leading to a shorter stature on average [2]. Research has also connected this genotype to a slightly smaller surface area of the cerebral cortex [3]. Crucially, the A allele is a recognized genetic risk factor for uterine leiomyomata, or uterine fibroids, in women [4]. This association suggests that the biological pathways regulating stature and benign smooth-muscle tumors are closely linked through HMGA2 [4]. Additionally, individuals with this genotype may have had slightly lower birth weights [5].
Shorter adult stature; Increased risk of uterine fibroids; Smaller cerebral cortex surface area.
Sample genotype: CA (Heterozygous)
Having a heterozygous genotype means carrying one copy of each allele, resulting in intermediate physical traits. Adult height and skeletal frame size are typically close to the population average [1]. The single C allele provides moderate expression of the HMGA2 growth regulator, balancing skeletal development [2]. Brain measurements, including the surface area of the cerebral cortex, generally fall within the typical range [3]. The risk of developing uterine fibroids is not significantly elevated compared to the general population [4]. Birth weight is also expected to be typical, reflecting balanced prenatal growth patterns [5].
Average adult height; Typical risk of uterine fibroids; Average cerebral cortex surface area.
Variants with shared genetic architecture
rs1042725 · HMGA2 Gene · Chr 12 · Height and Growth
rs1351394 · HMGA2 Gene · Chr 12 · Adult Height and Growth
rs11082304 · CABLES1 Gene · Chr 18 · Platelet Count and Size
Many sequence variants affecting diversity of adult human height.
Uterine leiomyomata and decreased height: a common HMGA2 predisposition allele.
The genetic architecture of human cortical folding.
Content updated August 2026.
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