Dermatoleukodystrophy is characterised by the association of a progressive leukodystrophy marked by generalised mental and motor impairment with the presence of thickened and wrinkled skin. It has been described in a Japanese brother and sister born to healthy parents. Both patients died in early childhood.

Hyperkeratosis is thickening of the outer layer of the skin, the stratum corneum, which is composed of large, polyhedral, plate-like envelopes filled with keratin which are the dead cells that have migrated up from the stratum granulosum.