A deleterious DNA change that is common in Scandinavia has been discovered in an elderly Maltese patient with amyotrophic lateral sclerosis (ALS), according to a new study by the University of Malta.

The study raises the possibility that the conquest of the Maltese islands by Viking descendants originally headed by Count Roger had left a lasting genetic mark on the island inhabitants. The study suggests that the Viking conquest of Europe may have played a role in the number of ALS cases today.

ALS is a progressive neurological disease that attacks the nerves that interact with the body’s muscles. The disease typically leads to complete paralysis of the body, robbing patients of their ability to walk, speak, eat and breathe. In Malta, about one individual every month develops ALS. Some ALS patients die months after the onset of symptoms while others survive for years.

It has reached the mainstream through the work of Bjorn Formosa, who was given the spotlight in the Lovin Malta documentary, A Little Smile.

The research team identified a Maltese patient with ALS who had a flaw in the superoxide dismutase 1 or SOD1 gene, the first gene identified to cause ALS nearly 3 decades ago. The change substitutes an amino acid in the antioxidant enzyme produced by the gene, affecting its function in the nerves.

The finding is the latest of an ongoing study aimed at identifying genetic and environmental factors associated with ALS through data and blood samples collected from ALS patients in Malta. 

Recently, the team discovered that Maltese ALS patients have a unique genetic makeup compared to their European counterparts. Furthermore, manual labourers in Malta were found to be twice as likely to be diagnosed with ALS.

“The DNA variant that we have exposed is quite common in Scandinavia and Finland but relatively inexistent in the South of Europe. Our discovery has implications not only on the genetic cause of ALS in Malta and Gozo but also on the genetic heritage of the Maltese and Gozitan population,” said the study’s lead researcher Prof. Ruben J. Cauchi, an associate professor of neurogenetics at the University.

Study co-authors are Maia Farrugia Wismayer, Dr Andrew Farrugia Wismayer, and Prof Neville Vassallo from the University of Malta; and, Dr Adrian Pace from Karin Grech and Gozo General Hospitals.

The study was funded by the University of Malta Research Excellence Fund, an Endeavour Scholarship (part-financed by the European Social Fund), and a Malta Council for Science & Technology Internationalisation Partnership Award.