LIM2 rs121913555: Understanding This Cataract-Linked Variant
rs121913555 is a rare genetic variant located within the LIM2 gene that has been classified as pathogenic in clinical databases. It is specifically associated with the development of Cataract 19, a condition characterized by the clouding of the eye's lens.
What each genotype means
Typical LIM2 gene profile
This genotype represents the common, non-pathogenic sequence for this specific location in the LIM2 gene. Individuals with this profile do not carry the specific mutation associated with Cataract 19 at this site.
This is the most common genotype found in the general population across all ancestries.
Carrier of LIM2 variant
This genotype indicates you carry one copy of the pathogenic variant (often referred to as p.Phe105Val) linked to Cataract 19. Because this condition is typically inherited in an autosomal recessive manner, carriers are generally not expected to exhibit the clinical features of the disease, though you should consult with a genetic counselor or clinician to understand your specific risk profile.
This genotype is extremely rare in the general population.
Increased risk for cataract
This genotype indicates you carry two copies of the pathogenic variant (p.Phe105Val) in the LIM2 gene. Research has linked this homozygous state to the development of Cataract 19, a condition characterized by lens opacity. Please discuss these results with an ophthalmologist or a medical geneticist to determine if clinical evaluation is appropriate.
This genotype is exceptionally rare and has been documented primarily in specific families or populations with a history of the condition.
What is rs121913555?
The variant rs121913555 is a single nucleotide polymorphism (SNP) situated within the LIM2 gene, which is located on human chromosome 19. In the context of genomics, a variant like this represents a specific change in the DNA sequence at a precise location. While the human genome is remarkably similar between individuals, these rare variations can occasionally alter the way genes function. This particular variant is well-documented in clinical databases, such as ClinVar, where it is categorized based on its potential impact on health. Unlike common variants that may only slightly influence a trait, pathogenic variants are identified because they change the protein-coding sequence or regulation of a gene in a way that disrupts normal biological processes. Because rs121913555 is rare, it is not typically included in standard consumer ancestry reports, and its presence is usually investigated in clinical settings when individuals or families present with specific, unexplained ocular symptoms.
The Role of the LIM2 Gene
The LIM2 gene provides instructions for producing a protein called Lens Intrinsic Membrane Protein 2. This protein is predominantly found in the lens of the eye, a structure that must remain transparent to focus light onto the retina. Within the lens, the LIM2 protein is integral to the structure and communication between lens fiber cells. These cells are densely packed and require specialized proteins to maintain their shape, transparency, and internal environment. Research suggests that LIM2 helps stabilize the cell membrane and facilitates interactions between neighboring cells, which is essential for the lens to maintain its crystalline clarity throughout a person's life. When the LIM2 gene is altered by a pathogenic variant, the resulting protein may be misfolded, unstable, or unable to perform its structural duties. This disruption can lead to the accumulation of proteins or cellular debris within the lens, eventually causing the clouding effect known as a cataract.
Research and Cataract Associations
The association between rs121913555 and cataracts is supported by clinical evidence identifying this variant as a cause of Cataract 19. Clinical studies and entries in the Online Mendelian Inheritance in Man (OMIM) database link mutations in LIM2 to various forms of inherited cataracts. The evidence for this specific variant is considered moderate to strong in clinical settings, as it has been identified in families where the trait follows a pattern of inheritance consistent with Mendelian disorders. However, it is important to note that cataracts can arise from many different genetic and environmental factors, including age, diabetes, and other genetic variants. Therefore, the presence of a pathogenic variant like rs121913555 serves as a specific explanation for lens opacities in those who carry it, distinct from the more common, age-related cataracts that affect the general population. Because cataracts are complex, researchers continue to study how different LIM2 variants result in varied clinical presentations, such as early-onset versus juvenile cataracts.
What This Information Means for You
Finding a pathogenic variant in your genetic report can be confusing, but it is essential to keep this information in perspective. If you have been identified as a carrier of a LIM2 variant, the most important step is to discuss these results with a clinical geneticist or an ophthalmologist. These professionals can explain how this variant relates to your specific health history and whether it explains any symptoms you may have. It is important to remember that a genetic variant is not a diagnosis on its own; clinical examination is required to determine if the variant is currently affecting your vision. You should never use genetic information to make medical decisions, such as surgery or treatment, without professional guidance. Furthermore, because this is a rare genetic finding, your clinician may recommend genetic counseling to help you and your family understand the potential implications for relatives.
How common is this variant?
According to major genomic databases like gnomAD, rs121913555 is an extremely rare variant. It does not appear at significant frequencies in the general population, and most data regarding this variant come from clinical cases and family studies.
Frequently asked questions
What is Cataract 19?
Cataract 19 is an inherited form of cataract, which causes a loss of lens transparency. It is often diagnosed when cataracts appear earlier than expected, such as in childhood or young adulthood.
Does having this variant mean I will definitely get cataracts?
Genetic variants like rs121913555 are linked to increased risk, but clinical penetrance—the likelihood that the variant will cause the condition—can vary. A specialist can help assess your specific risk based on your symptoms and family history.
Can I prevent cataracts if I have this variant?
There is no specific lifestyle change known to prevent cataracts caused by rare genetic variants in LIM2. Regular eye exams are the best way to monitor lens health and manage vision changes.
Why is this variant not on my ancestry report?
Most ancestry tests focus on common markers that reveal geographical origins. Rare clinical variants like rs121913555 are usually only identified through specialized clinical genetic testing.
Sources & further reading
Educational information only, last refreshed 10/3/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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