First gene therapy approach for MLC leukoencephalopathy designated as orphan drug

Researchers Raúl Estévez (UBNeuro-CIBERER) and Assumpció Bosch (UAB).
Researchers Raúl Estévez (UBNeuro-CIBERER) and Assumpció Bosch (UAB).
Research
(19/11/2021)

The European Medicines Agency (EMA) has designated as an orphan drug the first gene therapy approach to treat megalencephalic leukoencephalopathy with subcortical cysts (MLC), an ultra-rare disease that appears in childhood and leads to various neurological complications. Those behind this study, including the team of the Institute of Neurosciences of the UB (UBNeuro) led by Raúl Estévez, have managed to reduce the symptomatology of this disease in preclinical models.

Researchers Raúl Estévez (UBNeuro-CIBERER) and Assumpció Bosch (UAB).
Researchers Raúl Estévez (UBNeuro-CIBERER) and Assumpció Bosch (UAB).
Research
19/11/2021

The European Medicines Agency (EMA) has designated as an orphan drug the first gene therapy approach to treat megalencephalic leukoencephalopathy with subcortical cysts (MLC), an ultra-rare disease that appears in childhood and leads to various neurological complications. Those behind this study, including the team of the Institute of Neurosciences of the UB (UBNeuro) led by Raúl Estévez, have managed to reduce the symptomatology of this disease in preclinical models.

Megalencephalic leukoencephalopathy with Subcortical Cysts (MLC) is a form of leukodystrophy characterized by a macrocephaly that appears in childhood and leads to neurological symptoms that worsen over time: loss of motor functions, epilepsy and moderate mental retardation. Regarding the European population, it affects about 0.01 persons per every 10,000. So far, there is only supportive treatment, but no curative therapy for the affected patients.

This monogenic pathology is caused by mutations in one or other of two different genes. "In most cases, the disease is due to mutations in the Mlc1 gene", says Raúl Estévez, professor at the Department of Physiological Sciences, expert in the molecular mechanisms of the disease and member of the Center for Biomedical Research Network on Rare Diseases (CIBERER) and IDIBELL.

In brain biopsies of patients with MLC leukoencephalopathy, it has been observed that water accumulation takes place in the form of vacuoles both in the myelin -the insulating layer that forms around the nerves- and in the basic cells for maintaining neuronal function known as astrocytes, which surround the blood vessels. The researchers of this study have been able to improve the disease in the preclinical phase using a mouse model with the inactivated Mlc1 gene.

This is the first therapeutic approach that has been developed for MLC leukoencephalopathy and could have implications for the treatment of other diseases that affect motor functions, such as ataxias.

The designation of this orphan drug, promoted by CIBERER, has been the result of a research project co-led by the UB team and the research group on Gene Therapy led by Assumpció Bosch at the UAB. Researchers linked to the Vall d'Hebron Research Institute (VHIR) and the Catalan Institution for Research and Advanced Studies (ICREA) have also participated in its development.