Childhood-onset genetic white matter disorders of the brain in Northern Finland

Genetic white matter disorders are heritable neurological diseases that commonly have an onset during childhood and cause intellectual disability and other neurodevelopmental disorders. Salla disease, for example, is a leukodystrophy disorder belonging to the Finnish disease heritage characterised by intellectual disability and epilepsy. Based on previous studies, the incidence of genetic white matter disorders is estimated to be 1–13/100 000 live births.

This study examined the incidence, clinical findings, natural history, and genetic aetiologies of childhood-onset genetic white matter disorders in Northern Finland during 1990–2019. The cumulative incidence was 30/100 000 live births—considerably higher than previously estimated. The most common findings were motor developmental delay, intellectual disability, hypotonia, and spasticity.

The study included 20 disorders that were either recently characterised or not previously recognised as white matter disorders. These included TAF1C-related neurological disorder that has not been described previously. Additionally, a patient with a rare phenotype of neonatal Alexander disease was described with comparison to previously published cases. This study showed that childhood-onset genetic white matter disorders are more common than previously thought. The findings on the incidence and genetic phenotypes of specific disorders benefit the clinicians and researchers working with these complex diseases.