Incidence of neuronal perikaryal spheroids in neuronal ceroid lipofuscinoses (Batten disease).

The stored material in neuronal ceroid lipofuscinosis (NCL) undergoes, irrespective of the disease type, a uniform modification, altering profoundly its physical and histochemical properties. The process is accompanied by loss of immunodetectable epitopes of subunit c of mitochondrial ATP synthase (SCMAS) in the transformed storage material in NCL2 and NCL6 and of sphingolipid activator proteins (SAPs) A and D in NCL1, NCL2, and NCL6. It is restricted to certain subcortical brain nuclei, typically nucleus niger, dentatus, lentiformis, and thalamus. The process is coupled with progressive enlargement of the deposits caused probably by aggregation and fusion of the storage lysosomes. This ensues in formation of larger pleiomorphic perikaryal corpuscles, the spheroids being only one special form in the spectrum. The process was found to be most intensive in NCL2 brains. As the neuronal unmodified storage deposits tend also to be present in aggregate form, care must be taken to distinguish spheroids composed of modified from those composed of unmodified storage material.