An update on the connection between Melanoma and Parkinson’s disease

We have previously discussed the strange connection between Melanoma and Parkinson’s disease (click here to read that post).


That post included the curious observations that:

  • People with Parkinson’s disease are 2-8 times more likely to develop melanoma than people without Parkinson’s.
  • People with melanoma are almost 3 times more likely to develop Parkinson’s disease than someone without melanoma.

And we have no idea why (there is no shared genetic predisposition for the two conditions).

Research published this week, however, may begin to explain part of the connection:


Title: Parkinson disease (PARK) genes are somatically mutated in cutaneous melanoma.
Authors: Inzelberg R, Samuels Y, Azizi E, Qutob N, Inzelberg L, Domany E, Schechtman E, Friedman E.
Journal: Neurol Genet. 2016 Apr 13;2(3):e70.
PMID: 27123489     (This research article is OPEN ACCESS if you would like to read it)

In this study, the scientists looked at somatic mutations in cells from 246 tissue samples of melanoma.

What are somatic mutations?

Somatic mutations are genetic alteration that have been acquired by a cell that can then be passed to the progeny of that mutated cell (via cell division). These somatic mutations are different from ‘germline’ mutations, which are inherited genetic alterations that are present in the sperm and egg that were used in making each of us.


Somatic vs Germline mutations. Source: AutismScienceFoundation

In the 246 samples analysed, the researchers found 315,914 somatic mutations in 18,758 genes. Yes, that is a lot, but what was very interesting was their discovery of somatic mutations in many of the PARK genes.

What are PARK genes?

There are a number (approx. 20) genes that are now recognised as conferring vulnerability to developing Parkinson’s disease. These genes are referred to as PARK genes. They include the gene that makes the protein Alpha synuclein ( SNCA ) and many others with interesting names (like PINK1 and LRRK2). Approximately 15% of cases of Parkinson’s are believed to occur because of a mutation in one (or more) of the  PARK genes. As a result there is a lot of research being conducted on the PARK genes.

Were all of PARK genes mutated in the Melanoma samples?

Somatic mutation in 14 of the 15 PARK genes (that the researchers analysed) were present in the melanoma samples. This means that after the skin cells turned into melanoma cancer cells, they acquired mutations in some of the PARK genes. Overall, 48% of the analysed samples had a mutation in at least 1 PARK gene, and 25% had mutations in multiple PARK genes (2–8 mutated genes). One PARK gene in particular, PARK 8, was more significantly present in the melanoma cells than the others. PARK8 is also known as Leucine-rich repeat kinase 2 or LRRK2 (we have previously discussed Lrrk2 – click here to read that post). Three additional PARK genes (PARK2, PARK18, and PARK20) were also significantly present, but not as significant as Lrrk2.

So what does it all mean?

The researchers speculate in the discussion of their report about what the findings could mean, but it is interesting to note that many of the PARK genes are susceptible to acquiring mutations (particularly  Lrrk2). And this is important to consider when thinking about our development as individual human beings – even though you may not born with a particular mutation for Parkinson’s disease (you haven’t inherited it from our parents), somewhere along the developmental pathway (from egg fusing with sperm to full grown adult) you could acquire some of these mutations which would make you vulnerable to Parkinson’s disease.And here we should note that skin and brain share the same developmental source (called the ectoderm). A mutation in a PARK gene could occur during your development and you would never know.

We thought this was a very interesting study – certainly worthy of reporting here.

Another connection between skin and Parkinson’s disease

This is very interesting.

We have previously written blog posts dealing with the connection between melanoma and Parkinson’s disease. And now, there is new research providing a new link between another skin condition and Parkinson’s disease.


What is Rosacea?

Rosacea is a chronic skin condition, classically characterized by a redness of the face. This is the result of dilation of blood vessels in the facial skin, and is usually accompanied by pustules and swelling. Rosacea is indiscriminate in which age group it afflicts and there are four subtypes: three specifically affecting the skin and another affecting the eyes (ocular rosacea).


An example of Rosacea.Source: Medscape

Rosacea is diagnosed in women almost three times more than men. It is also more common in people between the ages of 30 and 50, and appears to have a preference for Caucasians of northwestern European descent (hence it’s nickname: the “curse of the Celts”).

What has this skin condition got to do with Parkinson’s disease?

Well, back in 2001 this study was published:


Title: Skin function and skin disorders in Parkinson’s disease.
Authors: Fischer M, Gemende I, Marsch WC, Fischer PA.
Journal: J Neural Transm. 2001;108(2):205-13.
PMID: 11314773

In this study, the researchers were investigating seborrheic dermatitis (similar to rosacea, this is an inflammation condition that presents itself as flaky, itchy, and red skin) and hyperhidrosis (abnormal increase in sweating) in Parkinson’s disease. They measured these afflictions in  70 people with Parkinson’s disease and 22 matched control subjects. Almost 20% of the people with Parkinson’s disease had seborrheic dermatitis and half of the Parkinson’s population had hyperhidrosis. The researchers also found that half of the Parkinson’s group also had abnormal sebum levels – sebum being a waxy substance produced by the skin (interestingly, we have previously mentioned sebum in a post about a lady who can smell Parkinson’s disease).

This was an interesting result, but it was never really followed up…until this last week, when another study was published:


Title: Exploring the Association Between Rosacea and Parkinson Disease: A Danish Nationwide Cohort Study.
Authors: Egeberg A, Hansen PR, Gislason GH, Thyssen JP.
Journal: JAMA Neurol. 2016 Mar 21. [Epub ahead of print]
PMID: 26999031

The size of this new study is amazing: the researchers looked at data from an national database which includes all Danish citizens 18 years or older from January 1, 1997 to December 31, 2011. That is a reference population of 5.4 million individuals!

Of these, 22 387 individuals (43.8% women) received a diagnosis of Parkinson disease between 1997 -2011, and 68 053 individuals (67.2% women) had a history of the skin condition rosacea.

The general population rate of Parkinson disease was 3.5 cases per 10 000 person. But in the population that had a history of rosacea the rate of Parkinson’s disease was 7.6 cases per 10 000 people – almost twice as high as the general population. Interestingly, when they looked at the subtypes of rosacea, the researchers found that there was a more than 2-fold increase in the risk of Parkinson disease in patients who had a history of ocular rosacea.

Even more interesting: treatment with tetracycline – an antibiotic – appears to have reduced the risk of Parkinson’s disease. The researchers also noted that people with severe rosacea have the same risk of developing Parkinson’s disease as do those who have more moderate rosacea.

This is an interesting study, further indicating a connection between the skin and Parkinson’s disease. Whether the relationship indicates anything causal or simply occurring in parallel is yet to be determined. But given similar previous association, we obviously need to take a closer look at skin.