FUCOSIDOSIS - A NEW MUTATION IN 2 UNRELAT ED GERMAN PATIENTS

Fucosidosis, a rare lysosomal storage disease due to nearly complete d eficiency of alpha-L-fucosidase, was diagnosed in two unrelated male G erman patients who exhibited typical symptoms of this disorder includi ng mental retardation, dysostosis multiplex, vacuolization of lymphocy tes and progressive neurologic deterioration by the age of 3.2 and 4 y ears, respectively. In both cases, activity of alpha-L-fucosidase in l eukocytes and cultivated fibroblasts was negligible. DNA analysis reve aled a nonsense mutation (G401X) in exon 7 of the fucosidase gene; thi s leads to a premature stop codon and C-terminal deletion of 61 amino acids from the protein. Discussion: On account of the mutation a uniqu e PFIMI restriction site is obliterated; this simplifies molecular dia gnosis of the G401X mutation. So far,the mutation G401X has not been f ound in any other population.