Rosacea's surprising genetic link

Nely Aldrich, M.D.Rosacea is a chronic skin disease of unclear etiology with limited treatment options. A recent study¹ of twins however has uncovered a definite genetic link in rosacea, shedding some light on this historically poorly understood disease.

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Researchers found that the disease occurs much more frequently in identical twins when compared with fraternal twins, and beyond this genetic predisposition, a significant association was also seen with a number of environmental as well as lifestyle factors that can exacerbate the disease.

This new data can help clinicians better understand the disease and could potentially help lead to a more effective treatment and management of rosacea.

“Rosacea research is still in its infancy and there’s not a whole lot we know about the disease but fortunately, this is slowly changing for the better,” according to Nely Aldrich, M.D., department of dermatology, University Hospitals Case Medical Center, Cleveland, Ohio, and main author of the study.

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“Many times, a patient will come in with a chronic skin disease such as rosacea and ask why they have it and not a family member or friend. Although we do not have a clear answer yet, adding to the frustration of patients, our research has helped to elucidate aspects of the disease that can begin to start the discussion of genetic predisposition as well as the modulation of environmental and lifestyle factors that could potentially help to ameliorate the symptoms of rosacea,” Dr. Aldrich says.

NEXT: Improving understanding

Improving understanding

Twin research has proven to be very useful in the past in better understanding the heritability of other diseases such as psoriasis, eczema and acne. According to Dr. Aldrich, the value of twin studies is in comparing concordance and discordance in the twin pairs, which can suggest heritability patterns and environmental effects on disease.

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This twin study included a cohort of 550 twins (233 identical and 42 fraternal twin pairs) aged 18 to 80 years who were surveyed regarding the risk factors implicated in rosacea. Questionnaires included information on gender, age, personal history of skin disease, Fitzpatrick Skin Type, smoking and alcohol history, cardiac comorbidity, lifetime physical activity, and lifetime sun-exposure accounting for geographical location.

Faculty dermatologists assessed the rosacea subtype and determined a rosacea score for each of the participants according to the National Rosacea Society (NRS) grading system. The ACE model, frequently used in twin studies and the criterion standard for genetic associations, was employed to calculate the contributions of genetic and environmental factors to the NRS score in study participants.

Results showed a mean rosacea score of 2.46 and 0.75 in identical and fraternal twin pairs, respectively. Identical twins were older, had lighter Fitzpatrick skin types and higher UV radiation exposure when compared to the fraternal twins. A higher association of NRS scores between identical versus fraternal twins was clearly seen, providing formal proof for a genetic contribution to rosacea, found to be 46% using the ACE model.

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Data also showed that a higher NRS score was also significantly associated with age, and lifetime UV radiation exposure. Other variables that were associated with rosacea disease in participants included BMI (body mass index), smoking, alcohol consumption, cardiovascular comorbidity, and skin cancer comorbidity. No association was found with eczema comorbidity, acne comorbidity, or physical activity level.

NEXT: Takeaways

Takeaways

The study confirms the importance of UV radiation as the single most important environmental factor associated with rosacea Dr. Aldrich says, and also uncovers other unexpected associations that impact the severity of the disease, such as BMI, the reasons for which remain unknown.

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According to Dr. Aldrich, the further elucidation of the risk factors of rosacea can help clinicians better advise their patients in terms of lifestyle changes which may positively impact their disease course and improve symptoms.

“Rosacea can significantly impact a patient’s psyche and socially stigmatize affected patients. The proof of the genetic component in rosacea can hopefully help placate our patients, as it is a confirmation that the disease is genetic and removes the mystery of ‘why me’. This knowledge could potentially help patients better psychologically manage their disease, and assist physicians in terms of patient counseling during the office visit,” Dr. Aldrich says.

Dr. Aldrich reports no relevant disclosures.

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Reference

1 Aldrich, N et al. Genetic vs environmental factors that correlate with rosacea: a cohort-based survey of twins. JAMA Dermatol. 2015 Aug 26. doi: 10.1001/jamadermatol.2015.2230.