Metachromatic leukodystrophy (MLD) is a neurodegenerative disease caused by the deficiency of a lysosomal enzyme called arylsulfatase A. It can start in childhood, adolescence or adulthood and is characterised by rapid demyelination of the central nervous system and peripheral associated with a build-up of sulfatides in the brain and kidneys.
Metachromatic leukodystrophy is an inherited disease transmitted in an autosomal recessive fashion. Thus, for a couple whose members are both carriers of the mutation, the risk of having an affected child (girl or boy) is 25% for each pregnancy.
It is estimated that this disease affects between 1 / 45,000 children at birth.