FOLLOW-UP-STUDY OF SUBUNIT-C OF MITOCHONDRIAL ATP SYNTHASE (SCMAS) INBATTEN-DISEASE AND IN UNRELATED LYSOSOMAL DISORDERS

Immunohistochemical and biochemical studies of subunit c of mitochondr ial ATP synthase (SCMAS) storage were carried out in neuronal ceroid l ipofuscinosis (NCL) and in a series of unrelated inherited and acquire d lysosomal disorders. In the NCL group, represented by the late infan tile, early juvenile and juvenile types, SCMAS storage was generalized neurovisceral, with considerable difference in the visceral storage p attern between the types. In late infantile NCL the SCMAS storage was intensive and corresponded to the generalized, autofluorescent, unifor mly curvilinear material, irrespective of the cell type affected. In b oth early juvenile and juvenile NCLs the SCMAS storage was strong and almost uniform in brain neurons, but did not correlate entirely with t he visceral autofluorescent storage pool, being undetectable in autofl uorescent storage deposits in a constant set of tissues. In the adult (Kufs) type, the brain neurons were stained with various intensity. In infantile NCL, SCMAS storage was restricted to some of the persisting neurons. In a series of inherited lysosomal enzymopathies and acquire d lysosomal disorders, excessive SCMAS accumulation was found only in secondary neuronal lipopigments. It occurred as an early and more unif orm phenomenon in mucopolysaccharidosis types I, II, IIIA and in polys ulphatase deficiency, or as a delayed varied phenomeno in protracted v ariants of mucolipidosis I, Niemann-Pick types A and C, and GM2 and GM 1 gangliosidoses. Neuronal ageing led to an irregular increase in immu nodetectable SCMAS epitope in some neuronal lipofuscin granules. There was no evidence of significant SCMAS lysosomal accumulation in non-ne ural cells in the whole group, regardless of whether lipofuscin or cer oid accumulation occurred or not. The neuronal SCMAS storage is thus n osologically a common unspecific phenomenon, which is especially ampli fied in NCL. The specificity of the NCL storage process is shown by th e fact that even lysosomes of non-neuronal cells in NCL accumulate SCM AS.