Leukodystrophies and genetic leukoencephalopathies in childhood: a national epidemiological study.

AIM: To report on the epidemiology of the brain white matter disorders of children identified via a national prospective study.
METHOD: Since 1997 a study of UK children with progressive intellectual and neurological deterioration (PIND) has used the British Paediatric Surveillance Unit system to identify children with progressive neurodegenerative disease. This paper reports on children in the study with brain white matter disorders.
RESULTS: Between May 1997 and November 2014 the PIND study identified 349 children with diagnosed leukodystrophies, giving an estimated UK lifetime risk of 31/million live births. There were 18 specific diseases in the group and relatively large numbers of affected children came from consanguineous Pakistani families. In addition there were 454 children with genetic leukoencephalopathies - in this group there were 38 diseases. 5.8% of children with scan evidence of brain white matter disorders did not receive a specific diagnosis.
INTERPRETATION: These unique prospectively-obtained national data avoid the selection bias inherent in reports from single centres. White matter disorders of the central nervous system comprise more than half of UK paediatric neurodegenerative diseases meeting the PIND criteria. This paper reports the lifetime risk/million live births for the commonest leukodystrophies, providing a basis for comparison with future studies.