Vitiligo: is there a genetic predisposition?

The skin is the largest organ of the body. Its main function is to cover and protect it from the outside. However, like any other organ, it is susceptible to certain diseases. Since it is such a large and external organ, the conditions that occur in it are more visible and conspicuous. 

 

One of these diseases, which affects 1% of the world’s population [1], is vitiligo. Although it has a lower incidence than other conditions, it is important to resolve doubts such as whether there is a predisposition to vitiligo or whether there are genetic causes that lead to it.

 

What is vitiligo?

 

Vitiligo is a chronic dermatological disorder that consists in the loss of skin color in certain areas of the body. It can develop equally in men and women and usually appears before the age of 30, although it can appear at any time in life [1]. It is not a serious or contagious disease, but it often has an emotional impact on the sufferer due to the vividness of its symptoms.

 

It occurs when immune cells destroy melanocytes, which are responsible for skin pigment [2]. In other words, the cells that produce melanin are attacked, dying or ceasing to function. It is, therefore, a failure of the immune system which, instead of protecting us from external aggressions, attacks and destroys healthy tissue. It therefore belongs to the type of diseases called autoimmune diseases. Later, we will discuss the possible genetic propensity to vitiligo.

 

Symptoms of vitiligo

 

Vitiligo begins with the appearance of light-colored spots, which usually start around the body orifices or armpits, nails, genitals and mammary areolas. They also tend to appear in areas where bones are prominent, such as elbows and knees. In addition, it sometimes affects the eyes and the mucosa of the nose and mouth [6]. 

 

Hair may also turn white in the affected areas. It has often been observed on the scalp, eyebrows, eyelashes and beard. Other less frequent symptoms of the disease describe an inflammation or swelling in the eye (known as uveitis) and inflammation of the ear. In addition, on a psychological level, people with vitiligo may develop low self-esteem and poor self-image, which can affect their quality of life [3].

 

What causes vitiligo?

 

The exact cause or causes that lead to vitiligo are unknown. Although there are currently different theories that try to explain it, there is no concrete evidence to support them [6]:

 

• Autoimmune theory: the immune system attacks melanocytes by interpreting them as a threat. This is the strongest theory that exists, especially in generalized vitiligo.
• Neurogenic theory: the nerve endings release a substance that is toxic to the cells that give color to the skin. This theory is supported in cases where the spots are in areas with nerve endings of a marrow root. It would correspond to segmental vitiligo.
• Self-destruction theory: melanocytes destroy themselves. This may be due to excess function or inability to eliminate toxins derived from skin cell metabolism, which would accumulate and become toxic to the melanocytes.

 

There is also talk of an integrative theory, since all these mechanisms could occur at the same time and explain some types of vitiligo.

 

Is vitiligo genetic?

 

There are still many unknowns about the origin of vitiligo, but it is known that there is a certain genetic predisposition to suffer from it [5]. People with family members with the disease are at an increased risk of contracting it. Twenty-five percent of diagnosed patients have a family member with the disease. In addition, the risk in first-degree relatives is about eight times higher [6].

 

Early studies establishing the genetic basis of vitiligo speak of a non-association of a single gene Mendelian inheritance pattern. On the contrary, it is now accepted that this disease is a polygenetic disorder, involving several genetic expressions and non-genetic factors that are related to its condition [7].

 

An example of the genes related to vitiligo is the CASP7 gene, which codes for the Caspase 7 protein. This protein is involved in apoptosis processes, i.e. cell death. 

 

On the other hand, it has been found that there is more propensity to vitiligo in people who already suffer from certain diseases related to a malfunction of the immune system such as: pernicious anemia, Addison’s disease, psoriasis, rheumatoid arthritis, systemic lupus erythematosus, thyroid disease or type 1 diabetes.

 

Know your genetic predisposition to vitiligo

 

The 24Genetics health test compares the DNA markers of people with vitiligo with people without the disease, thus identifying genetic differences. It is a statistical study, not a diagnostic tool, but it helps us in the prevention and early diagnosis not only of this disease, but of a multitude of health disorders that can affect us throughout life. If you are worried about your genetic predisposition to suffer from vitiligo, get out of doubts with this test. You can ask us any questions you may have without any obligation.

 

Bibliography:

 

[1] Vitiligo. DR. Pedro Redondo Bellón – Clínica Universidad de Navarra [accessed Oct. 2022] Available from: https://www.cun.es/enfermedades-tratamientos/enfermedades/vitiligo 

 

[2] MedlinePlus in Spanish [Internet]. English version reviewed by: Ramin Fathi, MD, FAAD, Director, Phoenix Surgical Dermatology Group, Phoenix, AZ. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial staff [reviewed Apr. 2020; accessed Oct. 2022] Available from: https://medlineplus.gov/spanish/ency/article/000831.htm. 

 

[3] Vitiligo. National Institute of Arthritis and Musculoskeletal and Skin Diseases. [accessed Oct. 2022] Available from: https://www.niams.nih.gov/health-topics/vitiligo 

 

[4] Vitiligo. Mayo Clinic [accessed Oct. 2022] Available at: https://www.mayoclinic.org/es-es/diseases-conditions/vitiligo/symptoms-causes/syc-20355912#:~:text=%20vitiligo%20is%20a%20affection%20of%20the%20skin%20in%20spots. 

 

[5] Information on vitiligo. Department of Communication and the Pedro Jaen Group Medical Team [accessed Oct. 2022] Available at: https://grupopedrojaen.com/especialistas-vitiligo/#:~:text=The%20s%C3%ADntoma%20m%C3%A1s%20evident%20of%20some%20m%20m%C3%A1s%20susceptible%20than%20others. 

 

[6] Vitiligo. Written by María Dolores Tuñon, reviewed by Doctor José Antonio Nuevo González – Webconsultas: Revista de salud y bienestar [published Dec. 2010; accessed Oct. 2022] Available from: https://www.webconsultas.com/vitiligo/causas-del-vitiligo-2166 

 

[7] Vitiligo What do genetic studies say? – Alexis Mendoza-León [published Sept. 2019; accessed Oct. 2022] Available from: https://piel-l.org/blog/47644