Introduction

Mucopolysaccharidosis (MPS) type III or Sanfilippo syndrome encompasses a group of four lysosomal storage disorders that are characterized by the inability to breakdown the glycosaminoglycan (GAG), heparan sulfate. Glycosaminoglycans are complex polysaccharides that are an important component of connective tissues and the extracellular matrix and heparan sulfate is an integral part of cell surfaces. Deficiency of one of the degradative enzymes results in the accumulation of partially degraded GAGs inside lysosomes, which leads to cell death and ultimately organ dysfunction. Each of the four Sanfilippo subtypes, A, B, C, and D, is caused by the deficiency of a different enzyme in the same degradative pathway for heparan sulfate: heparan-N-sulfatase (EC 3.10.1.1), alpha-N-acetylglucosaminidase (EC 3.2.1.50), acetyl-CoA N-acetyl transferase (EC 2.3.1.3), and N-acetylglucos-amine-6-sulfatase (EC 3.1.6.14), respectively. The incidence of MPS III has been estimated to be approximately 1 in 58,000 live births. All four Sanfilippo subtypes are autosomal recessive disorders but the genes have only been identified in types A, B, and D. The acetyl-CoA N-acetyl transferase enzyme that is deficient in type C patients is membrane-bound and this property has hindered its isolation and subsequent cloning. For subtype D, a total of 14 patients have been described worldwide and genetic defects have only recently been reported. The majority of Sanfilippo patients have subtypes A or B and it is these subtypes that will be focused on in this article.

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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