If you or a loved one has albinism, you know it’s a condition that affects pigment (color) in the skin, hair, and eyes—along with vision challenges like nystagmus (uncontrolled eye movements) or reduced visual acuity. But did you know that scientists are still uncovering why albinism happens in some people and not others? A recent study of Hungarian patients with albinism offers new insights into the genetic roots of the condition—including a possible “digenic” (two-gene) link that could explain why some cases are harder to diagnose.
In this article, we’ll break down what this research means for you, your family, and the future of albinism care.
What You’ll Learn
This study focuses on a big question in albinism research: why do some people with albinism not have the “classic” genetic changes known to cause the condition? (Scientists call this “missing heritability.”) The researchers found that for some patients, albinism might be driven by two genes working together—not just one. This is a big deal because it could help more people get accurate diagnoses, understand their family risk, and even pave the way for targeted treatments.
A Quick Look at Albinism
Albinism is a rare genetic condition that reduces the amount of melanin (the pigment that gives color to skin, hair, and eyes) in the body. Most types of albinism are inherited in an autosomal recessive way—meaning you need two copies of a faulty gene (one from each parent) to develop the condition.
Common symptoms include:
- Very light skin, hair, and eyes (though some people have milder pigment loss)
- Vision problems (e.g., nystagmus, farsightedness, or sensitivity to light)
- Increased risk of skin cancer (due to low melanin protection)
Until now, scientists knew of 22 genes linked to albinism. But this study shows there’s more to the story.
Why Genetic Discoveries Matter for Rare Diseases Like Albinism
For rare conditions, finding the right gene can be life-changing. Here’s why:
- Diagnosis: Genetic testing can confirm albinism and rule out other conditions with similar symptoms.
- Family Planning: Knowing which genes are involved helps families understand their risk of passing albinism to future children.
- Treatments: Targeted therapies (like gene therapy) often rely on knowing exactly which gene is faulty.
Albinism affects about 1 in 17,000 people worldwide, but many cases still lack a clear genetic explanation. This study aims to fill that gap.
What New Genetic Clue Did Researchers Find?
The team studied 17 Hungarian patients with albinism. First, they tested for changes in the 22 known albinism genes. They found a clear genetic cause in 11 patients (64.7%)—mostly in genes like TYR (tyrosinase) or OCA2 (oculocutaneous albinism type 2), which are critical for melanin production.
But for 6 patients (35.3%), the “classic” genes didn’t explain their albinism. This is where the new findings come in:
1. A New Gene Variant: TPCN2 (N687S)
In one 15-year-old patient, the researchers found a rare change (called a “variant”) in a gene called TPCN2. This gene makes a protein (TPC2) that helps regulate the pH (acid levels) in melanosomes—tiny structures in cells that make melanin.
The patient’s mother also had the TPCN2 variant but did not have albinism. This told researchers the variant alone isn’t enough to cause the condition.
2. Digenic Inheritance: Two Genes Working Together
The team then looked deeper at the patient’s DNA and found another variant in the OCA2 gene (R305W), which is known to affect pigment. The patient inherited the TPCN2 variant from their mother and the OCA2 variant from their father—a combination no one else in the family had.
Scientists think these two variants might “add up” to cause albinism. This is called digenic inheritance—when two different gene changes (one from each parent) work together to cause a condition.
3. What Does This Mean for the TPCN2 Gene?
The TPCN2 variant (N687S) is new to science, but the researchers tested it in lab cells. They found it didn’t change how the TPC2 protein works on its own. But when combined with the OCA2 variant, it might disrupt melanin production—explaining why the patient has albinism while their mother (who only has the TPCN2 variant) does not.
What Does This Mean for Patients and Families?
1. More Accurate Diagnoses
For the 35% of albinism cases with “missing heritability,” this study suggests looking for two genes instead of one. This could help more people get a definitive genetic diagnosis—something that’s often missing for rare conditions.
2. Better Family Risk Information
If you have a family member with albinism, knowing about digenic inheritance can help you understand your risk. For example, if one parent carries a TPCN2 variant and the other carries an OCA2 variant, their child might inherit both and develop albinism—even if neither parent has the condition.
3. Future Treatments
Targeted therapies (like gene editing or drugs that fix faulty proteins) rely on knowing exactly which genes are involved. This study adds TPCN2 and OCA2 to the list of genes linked to albinism, opening doors for new research.
4. Explaining Symptom Variation
Albinism looks different in everyone—some people have very light skin, while others have milder pigment loss. The combination of TPCN2 and OCA2 variants might explain why symptoms vary so much.
Important Considerations
- Not Everyone with Albinism Has These Variants: The TPCN2 (N687S) variant was only found in one patient in this study. Most cases of albinism are still caused by changes in the 22 known genes.
- Genetic Testing Is Complex: Interpreting gene variants requires a specialist (like a genetic counselor). A “variant” doesn’t always mean “disease-causing”—it depends on how the change affects the protein.
- This Is Early Research: The study included a small number of patients (17). More research is needed to confirm if digenic inheritance is common in albinism.
Key Points to Remember
- Missing Heritability: About 1 in 3 people with albinism don’t have changes in the 22 known albinism genes.
- Digenic Link: For some patients, albinism might be caused by two genes working together (e.g., TPCN2 + OCA2).
- Hope for Diagnosis: This research could help more people get accurate genetic diagnoses.
- Future Treatments: Targeted therapies for albinism may one day focus on genes like TPCN2 and OCA2.
Talk to Your Doctor or a Genetic Counselor
If you’re interested in genetic testing for albinism, start by talking to your doctor or a genetic counselor. They can help you:
- Understand your risk of passing albinism to your children.
- Interpret genetic test results.
- Explore support resources for albinism.
Remember: You’re not alone. Albinism is a manageable condition, and new research is bringing us closer to better care.
This article is based on a 2024 study published in the International Journal of Molecular Sciences by researchers from Hungary, Germany, and the U.S. The study highlights the importance of looking beyond “classic” genes to understand rare conditions like albinism. For more information, ask your doctor or visit trusted resources like the National Organization for Albinism and Hypopigmentation (NOAH).