passages.id: split_5_test_2537_passage
passages.type: progene_text
passages.text: Asp-335-Val and Arg-370-Trp substitutions each cause a complete loss of enzyme activity and are associated with the most severe form of the human disease , whereas the Arg-370-Gln-substituted enzyme retains some residual activity , being found in a patient suffering from the milder juvenile form of the disease .