A Canadian male child with fucosidosis and dystonia is reported from the Department of Biochemical Genetics, University of Western Ontario, London, Ontario, Canada. All milestones were delayed, he crawled at 14 months, walked by 18 months, and his developmental quotient at 27 months was 50. At 46 months the quotient had dropped to 35. At 5 years, dystonic posturing of the left leg began, and 6 months later, he had episodes of choking, staring spells, and nocturnal apnea. At 7 years,he could not walk or talk, and the dystonia was bilateral. An angiokeratomatous rash became generalized. Cultured lymphoblasts showed absent a-fucosidase activity and protein. He was homozygous for the Q422X mutation. 
COMMENT. Fucosidosis is a progressive neurodegenerative disease presenting in early childhood and manifested by loss of mental and motor function, with early hypotonia followed by increasing spasticity and seizures. Dystonia evident in this report had not previously been reported. Dysmorphic features and skeletal changes similar to those in mucopolysaccharidoses develop and include dwarfism, dysostosis multiplex, and visceromegaly. A skin rash occurs in those surviving childhood. The disease is caused by an autosomal recessive genetic deficiency of the lysosomal enzyme a-L-fucosidase. Seventy seven patient reports were reviewed in 1991. Menkes JH refers to two forms, type 1 without, and type 2 with angiokeratoma of the skin, particularly of the gingiva and genitalia.