HLA Region rs9263738: What Your Genotype Means
The genetic variant rs9263738 is located within the major histocompatibility complex (MHC) region on chromosome 6. Research has identified this variant as being significantly associated with an increased risk of unexplained recurrent pregnancy loss in certain populations.
What each genotype means
Increased risk profile
This genotype is associated with a statistically higher risk of unexplained recurrent pregnancy loss in certain populations, such as those of Japanese ancestry. This variant is located in the MHC region, which plays a critical role in immune function during pregnancy. Please discuss your reproductive health history and any concerns with a qualified healthcare provider or genetic counselor.
This genotype is common, with the risk allele frequency reported at approximately 87% in some studied populations.
Intermediate risk profile
Carrying one copy of each allele places you in an intermediate category regarding the statistical association with unexplained recurrent pregnancy loss. Because this variant is part of a complex region of the genome, its influence can be modified by other linked genetic factors. Consult with a reproductive specialist to understand how this information relates to your personal health context.
This heterozygous genotype is observed frequently in populations where the variant is common.
Lower risk profile
This genotype does not carry the specific risk-associated allele identified in studies of unexplained recurrent pregnancy loss. While this suggests a lower statistical association with this specific genetic marker, reproductive health is influenced by many factors beyond a single variant. Always discuss your family history and reproductive goals with a medical professional.
This genotype is less common than the risk-associated homozygous state in populations where the A allele is the primary risk factor.
Understanding the Variant and Its Location
The variant rs9263738 is a single nucleotide polymorphism (SNP) situated on chromosome 6 at position 31,109,767 (hg19). This location places it within the major histocompatibility complex (MHC), a dense cluster of genes that plays a critical role in the human immune system. The MHC region is highly polymorphic, meaning it contains a vast amount of genetic variation between individuals. Because of its complexity and its involvement in immune function, variants in this region are frequently studied for their potential roles in conditions where the immune system interacts with foreign or semi-foreign tissues, such as during pregnancy. The rs9263738 variant is characterized by two alleles, T and C, with the T allele identified in recent studies as having a susceptible effect regarding reproductive outcomes.
The Role of the HLA Region
The HLA (Human Leukocyte Antigen) genes within the MHC region are responsible for encoding proteins that present antigens to the immune system, helping it distinguish between 'self' and 'non-self' cells. During pregnancy, the maternal immune system must tolerate the fetus, which carries paternal genetic material that could otherwise be recognized as foreign. This delicate balance of immune tolerance is essential for a successful pregnancy. Research suggests that specific HLA alleles and haplotypes—groups of genes inherited together—can influence this maternal-fetal interface. Variations in these genes may alter how the immune system recognizes the developing fetus, potentially contributing to complications like unexplained recurrent pregnancy loss (uRPL). Understanding these genetic factors is a growing area of reproductive immunology, aiming to clarify why some pregnancies fail without other identifiable clinical causes.
Research and Evidence Strength
The association between rs9263738 and unexplained recurrent pregnancy loss is supported by genome-wide association studies (GWAS). A notable study involving individuals of Japanese ancestry identified this variant as a lead signal for uRPL, with a reported odds ratio of 1.51. The researchers fine-mapped this association to specific classical HLA alleles, including HLA-C*12:02, HLA-B*52:01, and HLA-DRB1*15:02, which form a long-range haplotype. While the statistical evidence for this association is strong within the studied population, it is important to note that genetic associations can be highly ancestry-specific. The evidence strength is considered moderate because, while the link to uRPL is statistically significant in specific cohorts, the biological mechanisms are complex and multifactorial. Further research across diverse global populations is necessary to determine if this association holds true universally or if it is specific to certain genetic backgrounds.
Population Frequency and Interpretation
The rs9263738 variant is considered common, meaning it is found frequently across various human populations. In the context of the Japanese study, the risk allele frequency was observed to be approximately 0.871 in controls. Because this variant is common, carrying the risk allele does not mean that an individual will experience pregnancy loss; rather, it represents a statistical increase in risk within a population-level analysis. It is crucial to understand that reproductive health is influenced by a wide array of factors, including environmental, hormonal, and other genetic influences. This information should not be used for personal diagnosis or to predict individual pregnancy outcomes. If you have concerns about reproductive health or pregnancy history, it is essential to consult with a reproductive endocrinologist or a qualified medical professional who can provide personalized clinical guidance.
How common is this variant?
The rs9263738 variant is a common polymorphism found across various ancestral groups, with the risk allele frequency observed at approximately 0.871 in Japanese control populations.
Frequently asked questions
Does having the rs9263738 risk allele mean I will have a pregnancy loss?
No. This variant is associated with a statistical increase in risk at the population level, not a certainty for any individual. Many factors contribute to pregnancy outcomes, and most people with this variant have healthy pregnancies.
Can I use this genetic information to diagnose the cause of my pregnancy loss?
No. Genetic variants like rs9263738 are only one piece of a very complex puzzle. You should discuss your medical history and any concerns with a reproductive specialist who can evaluate all clinical factors.
Is this variant found in all populations?
The variant is common, but the specific associations with pregnancy loss have been primarily studied in populations of Japanese ancestry. Genetic associations can vary significantly between different ethnic and ancestral groups.
What should I do if I am concerned about my genetic risk for pregnancy loss?
The best course of action is to speak with a healthcare provider, such as a reproductive endocrinologist or a genetic counselor. They can provide context based on your personal health history and current clinical guidelines.
Sources & further reading
Educational information only, last refreshed 10/5/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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