How to Treat Hereditary, Rare Diseases

March 3, 2026

Much research has been undertaken over many decades on diseases that affect large populations, such as cancer and heart disease. Therapeutic approaches have considerably improved as a result of long-term research work on diseases that affect a huge number of individuals.

However, there are many diseases that affect just a handful of people. These diseases often fly under the radar and are far less researched. They include quite a few rare, hereditary diseases, such as DOOR syndrome, which is especially found in Canada and the Middle East.

A team of scientists is now in the process of trying to change this.
“For some hereditary, rare diseases, there is currently no cure. However, gene therapy is a possible solution, and we are now testing various strategies using gene therapy,” says Magnar Bjoras, a professor at the Norwegian University of Science and Technology (NTNU’s) Department of Clinical and Molecular Medicine.

He has established a research team at NTNU and Oslo University Hospital that conducts basic research on rare, hereditary diseases with a long-term goal of finding new therapies. One of the rare diseases for which there is currently no medication or treatment is called DOOR syndrome.

This is a congenital disorder that involves multiple abnormalities. DOOR is an acronym for the main features of the disorder: Deafness, Onychodystrophy (short or absent nails), Osteodystrophy (short fingers and toes) and developmental delay and intellectual disability (previously called mental Retardation).

DOOR syndrome is hereditary and is caused by the lack of a specific protein in the genes called OXR1 (OXidation Resistance gene 1).
“Due to lack of this protein, the brain cells are unable to develop as they should. As a result, the brain cells either become dysfunctional or simply die,” says Magnar Bjoras. In order to investigate whether there is a way to prevent this from happening, the
Bjoras team has carried out tests inside mini-brains that they grow in their lab.

The Bjoras team has been working on growing mini-organs such as mini-brains, mini-lungs and mini-eyes since 2018. The scientists use the mini-organs to test drugs and gene therapy.

In order to grow mini-brains for their research on DOOR syndrome, the research team needed cells from people who have this disease.

A number of cases have been registered in Canada and the Middle East, and the research being done in Norway is based on skin cells from people who have DOOR syndrome.

“In the laboratory, we have transformed the skin cells into embryo cells. We have reversed the development in the skin cells so that they return to the foetal stage and become like the first cells that form in humans. We have then used these stem cells to create mini-brains,” says Bjoras.

Using skin cells from people with DOOR syndrome, the scientists have recreated the disease in the mini-brains. They can then use these mini-brains to test out therapies for this disease. “In the laboratory, we have transformed the skin cells into embryo cells. We have reversed the development in the skin cells so that they return to the foetal stage and become like the first cells that form in humans. We have then used these stem cells to create mini-brains,” says Bjoras.

Starting production of the missing protein The work has given the scientists insight into the reasons why patients develop disease – and thus also ideas for treatment strategies. Gene therapy is one possible treatment where the brain cells can be made to start producing the missing protein.

A virus is actually used as a messenger that delivers the necessary production information to the brain cells. “As a follow-up to our published work, we are now testing virus-based gene therapy as a treatment for this
disease,” Bjoras said.