Diagnostics of mucopolysaccharidoses presented through the case of sanfilippo syndrome

Abstract

Mucopolysaccharidoses (MPS) are recessive inheritable, progressive diseases of disordered degradation and storage of acid glucosaminoglycans. A five-year old child with psychomotor development retardation, which started at his age of two, was presented in our study. Clinical examination showed big head with rough facial features, skeleton deformities and hepatosplenomegaly. The diagnosis Dysostosis epifisealis multiplex was also confirmed by the X-ray examination of skeleton. Karyotype: 46, XY. Mental retardation: IQ--48. Clinically suspected mucopolysaccharidosis called for metabolic screening of first morning urine and the positive toluidine blue test result indicated the increased excretion of mucopolysaccharides. Further enzyme analyses of peripheral blood leucocytes confirmed the heparin sulphate sulphatase deficiency on the basis of which A (MPS III) Sanfilippo syndrome was defined. Our patient was born as a twin sibling. The other sibling is clinically healthy and of normal metabolic screening. It was not possible to define precisely the healthy heterozygote by testing the enzyme activities. A large number of mutations at various loci and big genetic heterogeneity of mucopolysaccharidoses made molecular diagnostics difficult. In the subsequent pregnancy, the mother was recommended prenatal diagnostics by enzyme analysis from the cultured chorionic villus. The prognosis of the presented patient is bad, the course of the disease is progressive and the patient can be expected to die in spastic tetraplegia in the second decade of life. The treatment is symptomatic for the time being.