SPATA16 rs75834899: Understanding Reproductive Genetics
The rs75834899 variant is located within the SPATA16 gene, which is primarily expressed in the testes and plays a critical role in sperm development. Research has linked specific mutations in this gene to globozoospermia, a rare condition characterized by round-headed sperm that lack an acrosome, leading to male infertility.
What each genotype means
Typical sperm morphology
You carry two reference copies of the SPATA16 gene at this position. This genotype is not associated with globozoospermia or round-headed sperm morphology defects. Your SPATA16-related spermatogenesis function is expected to be typical.
Carried by more than 99.9% of individuals across all global populations in gnomAD.
Unaffected carrier status
You carry one copy of the rare SPATA16 missense variant. Because SPATA16-related globozoospermia and spermatogenic failure 6 are inherited in an autosomal recessive manner, heterozygous carriers are typically unaffected and maintain normal fertility. Transmission to offspring may be relevant if a reproductive partner also carries a pathogenic SPATA16 variant.
Extremely rare across all surveyed populations, occurring in fewer than 1 in 10,000 individuals globally.
Globozoospermia risk
You carry two copies of this rare missense variant in the SPATA16 gene. In clinical research, homozygous pathogenic variants in SPATA16 are strongly linked to autosomal recessive spermatogenic failure 6, characterized by round-headed acrosomeless spermatozoa and primary male infertility. Individuals interested in biological family planning can discuss reproductive technologies such as intracytoplasmic sperm injection with a reproductive specialist.
Exceptionally rare globally, documented in isolated consanguineous pedigrees and absent in general population databases.
What is the SPATA16 Gene?
The SPATA16 gene, which stands for Spermatogenesis Associated 16, provides instructions for creating a protein that is expressed almost exclusively in the testes. This protein is essential for the process of spermiogenesis, the final stage of sperm development where round spermatids transform into mature, elongated spermatozoa. A key feature of this transformation is the formation of the acrosome, a cap-like structure on the head of the sperm that contains enzymes necessary for penetrating the egg during fertilization. Because SPATA16 is vital for this structural development, disruptions in its function can lead to significant issues with sperm morphology and, consequently, male fertility.
Understanding the Variant and Globozoospermia
Globozoospermia is a rare form of teratozoospermia, affecting less than 0.1% of infertile men. It is defined by the presence of round-headed sperm that lack the acrosome, rendering them unable to fertilize an egg naturally. Scientific literature has identified that homozygous mutations in the SPATA16 gene can be a causative factor for this condition. While the specific variant rs75834899 is cataloged in relation to this gene, it is important to note that the evidence linking specific SNPs to clinical outcomes is often limited. Research into SPATA16 has largely focused on identifying how structural defects in the protein prevent the proper formation of the acrosome, thereby disrupting the complex biological pathway required for healthy sperm production.
Evidence and Scientific Context
The association between SPATA16 and male infertility was first established through studies of consanguineous families where homozygous mutations were identified in affected brothers. Subsequent research, including studies using CRISPR/Cas9-mediated mouse models, has confirmed that SPATA16 is indispensable for male fertility. However, not all mutations in the gene result in the same clinical severity. For instance, some point mutations identified in patients have shown variable effects in animal models, suggesting that the functional impact of a variant can depend on its specific location within the gene and the nature of the genetic change. Because this is a rare condition, the evidence base remains focused on specific case reports and small cohort studies rather than large-scale population-wide associations.
What This Information Means for You
If you have encountered this variant in a genetic report, it is essential to understand that genetic testing for rare reproductive conditions is complex and should be interpreted by a qualified medical professional or genetic counselor. A variant identified in a database does not constitute a medical diagnosis. Many genetic variations are benign and have no impact on health or fertility. If you are concerned about reproductive health or fertility, the most appropriate step is to consult with a reproductive endocrinologist or a urologist who specializes in male infertility. They can provide context based on your personal medical history, physical examinations, and standard clinical tests like semen analysis, which are far more diagnostic than a single SNP result.
How common is this variant?
The rs75834899 variant is considered a rare genetic variant. Population frequency data for specific rare variants is often limited in large-scale databases, and clinical significance is typically only observed in rare, homozygous cases.
Frequently asked questions
What is globozoospermia?
Globozoospermia is a rare condition where sperm have round heads and lack an acrosome, which is the cap needed to fertilize an egg. It is a known cause of male infertility.
Does having a SPATA16 variant mean I am infertile?
No. A single genetic variant does not diagnose infertility. Infertility is a complex condition with many causes, and you should consult a fertility specialist for a proper evaluation.
Is SPATA16 testing standard for fertility?
No, it is not a routine test. Genetic testing for specific genes like SPATA16 is usually reserved for cases where a doctor suspects a specific genetic cause for severe sperm morphology issues.
Can I change my genetics if I have this variant?
No, your genetic sequence is inherited and cannot be changed. However, understanding your genetic profile can help you and your doctor make informed decisions about your reproductive health.
Sources & further reading
Educational information only, last refreshed 10/19/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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A missense change in SPATA16 that impairs Golgi-derived acrosome vesicle transport, causing round-headed sperm morphology (globozoospermia) and fertilization failure.
Loss-of-function variant in SPATA16 causing globozoospermia and male infertility.