Premium
Heterogeneity of Morquio disease
Author(s) -
Beck M.,
Glössl J.,
Grubisic A.,
Spranger J.
Publication year - 1986
Publication title -
clinical genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 102
eISSN - 1399-0004
pISSN - 0009-9163
DOI - 10.1111/j.1399-0004.1986.tb01262.x
Subject(s) - sulfatase , neuraminidase , disease , mucopolysaccharidosis , lysosomal storage disease , enzyme , hunter syndrome , mucopolysaccharidosis type ii , medicine , biology , enzyme replacement therapy , endocrinology , biochemistry
Further clinical heterogeneity of Morquio disease, mucopolysaccharidosis IV (MPS IV), is delineated by the observation of a 30‐year‐old man with unusually mild clinical manifestations. He is 156 cm tall, has comparatively mild skeletal abnormalities and fine corneal deposits. Keratosulfaturia is absent. N‐Acetylgalactosamine‐6‐sulfate (GalNAc‐6‐S) sulfatase (E.C. 3.1.6. –) was markedly reduced in his fibroblasts. The residual enzyme activity exhibited a pH profile comparable to that of patients with the “classical” form of the disorder. From our observation and a review of the literature it is concluded that Morquio disease can be divided in several subgroups: besides the severe (“classical”) type A there exist an intermediate and a mild form that are also caused by a GalNAc‐6‐S sulfatase deficiency. A late‐onset variant of Morquio disease, which is due to a deficiency of β‐galactosidase, has been classified as type B. In addition, patients with mild manifestation of the disease and normal activities in fibroblasts of GalNAc‐6‐S sulfatase and β‐galactosidase have been observed (type C). The genetic nature of the broad clinical variability of Morquio disease is incompletely understood: it is partially caused by different enzyme defects. Other factors thought to influence the clinical expression include the pH profile of the residual enzyme activity and an additional neuraminidase defect.