Genetic studies have identified six genes—CLNj_3, CLN5,6, and CLN8—underlying NCL1-3, NCL5,6, and NCL8, respectively (Table 1). The function of each gene is yet unclear, although two lysosomal peptidases, pal-mitoyl-protein thioesterase 1 (PPT1) and tripeptidyl peptidase 1 (TPP1), have been characterized. The CLN3-encoded protein, Battenin; the CLN6-encoded protein, CLN6p; and the CLN8-encoded protein, CLN8p are predicted to be transmembrane proteins. The CLN5-encoded protein, CLN5p, was determined to be a lysosomal soluble protein, even if it contains hydrophobic segments. A total of 151 mutations have been identified, including 41 at locus CLN 1, 52 at CLN2, 31 at CLN3, 4 at CLN5, 22 at CLN6, and 1 at CLN8 (http://www.ucl.ac.uk/ ncl). Heterogeneity, both phenotypically and genotypi-cally, has been demonstrated. CLN1 mutations can result in clinical onset at infantile, late-infantile, or adult age; however, late-infantile onset can be caused by mutations of CLN2, CLN3, CLN5, CLN6, and CLN8 genes.[2,4-6]
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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.