Pj. Meikle et al., DIAGNOSIS OF LYSOSOMAL STORAGE DISORDERS - EVALUATION OF LYSOSOME-ASSOCIATED MEMBRANE-PROTEIN LAMP-1 AS A DIAGNOSTIC MARKER, Clinical chemistry, 43(8), 1997, pp. 1325-1335
Early diagnosis of lysosomal storage disorders (LSDs), before the onse
t of irreversible pathologies, will be a key factor in the development
of effective therapies for many of these disorders. Newborn screening
offers a potential mechanism for the early detection of these disrode
rs. From studies of both normal and LSD-affected human skin fibroblast
s we identified the lysosome-associated membrane protein LAMP-1 as a p
otential diagnostic marker. We have developed a sensitive method for t
he quantification of this protein with a time-resolved fluorescence: i
mmunoassay. A soluble form of LAMP-1 was observed in plasma samples, a
nd determination of 152 unaffected individuals gave a median value of
303 mu g/L with the 5th and 95th percentile at 175 and 448 mu g/L resp
ectively. Plasma samples from 320 LSD-affected individuals representin
g 25 different disorders were assayed. We observed that 17 of the 25 d
isorder groups tested had >88% of individuals above the 95th percentil
e of the control population, with 12 groups having 100% above the 95th
percentile. Overall, 72% of patients had LAMP-1 concentrations above
the 95th percentile of the unpartitioned control population. We sugges
t that LAMP-1 may be a useful marker in newborn screening for LSDs.