[Enzymatic diagnosis of 47 cases with mucopolysaccharidosis].
OBJECTIVE
With the emergence of enzyme replacement therapy and progress in bone marrow transplantation, treatment of mucopolysaccharidosis (MPS) is much more promising than ever. In order to benefit from these therapies, determination of the defective enzyme is the prerequisite for any individual patient. To make definite diagnosis for patients suspected of having MPS clinically, the authors established six lysosomal enzymatic assays for leucocytes, including alpha-L-iduronidase, iduronate-2-sulfatase, N-acetylgalactosamine 6-sulfatase, beta-galactosidase, arylsulfatase B, beta-glucuronidase, which are the corresponding enzymes of type I, type II, type IVA, type IVB, type VI, and type VII, respectively.


METHODS
Seventy patients suspected of having MPS were enrolled from outpatient clinics of the Department of Pediatric Endocrinologic, Genetic and Metabolic Diseases in Xinhua Hospital. Their ages spanned from 10 months to 25 years with the average age 5.7 years. Of them 49 were male and 21 were female. Leukocytes were isolated with Dextran from peripheral blood of suspected patients. Activity of leukocyte alpha-L-iduronidase, iduronate-2-sulfatase, N-acetylgalactosamine 6-sulfatase, beta-galactosidase, beta-glucuronidase were measured using their specific artificial fluorescent substrates, while arylsulfatase B were determined by colorimetric assay with dipotassium 2-hydroxy-5-nitrophenyl sulfate as the substrate.


RESULTS
Of the 70 clinically suspected cases totally 47 were confirmed of having mucopolysaccharidosis, of whom 7 cases were type I, 28 cases type II, 12 cases type IVA. These data show that type II is the predominant form of MPS in China, succeeded by MPS type IVA. It was also noted that type II has the most variable clinical manifestations and 8 out of 12 type IVA patients had the unique lax joints.


CONCLUSIONS
The present study suggest that type II might be the predominant form of MPS cases in China, followed by type IVA and type I.
Zhang
Hui-Wen
HW
Department of Paediatric Endocrinologic, Genetic and Metabolic Diseases, Shanghai Institute of Pediatric Research, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200092, China.
Wang
Yu
Y
Ye
Jun
J
Qiu
Wen-Juan
WJ
Han
Lian-Shu
LS
Gao
Xiao-Lan
XL
Gu
Xue-Fan
XF
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007066:Iduronate Sulfatase / Q000378:metabolism; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009083:Mucopolysaccharidoses / Q000145:classification / Q000175:diagnosis* / Q000201:enzymology*; D055815:Young Adult
D007066:Iduronate Sulfatase