We report a new neurocutaneous syndrome of apparent autosomal recessive inheritance consisting of early-childhood-onset palmoplantar keratoderma followed in adulthood by progressive tetrapyramidal syndrome and cognitive impairment. Of the four affected siblings, two were available for evaluation. Investigation disclosed cerebral white-matter involvement on MRI and arylsulfatase A pseudodeficiency carrier state, which was also identified in clinically unaffected family members. Since skin biopsies showed dermal connective tissue abnormalities, we studied collagens I, III, and VI biosynthesis. Northern blotting of RNA extracted from cultured skin fibroblasts revealed an increased steady-state messenger RNA (mRNA) level of alpha 1(VI) collagen, whereas no differences were detected for pro alpha 1(I), pro alpha 1(III), and tropoelastin mRNAs. The skin content of collagen and total protein was higher in the patients than in controls. We suggest that an extracellular matrix abnormality may be involved in the pathogenesis of this disorder.