Genetic heterogeneity in neuronal ceroid lipofuscinosis (NCL): evidence that the late-infantile subtype (Jansky-Bielschowsky disease; CLN2) is not an allelic form of the juvenile or infantile subtypes.
We have collected 122 late-infantile neuronal ceroid lipofuscinosis (LINCL, CLN2) and 191 juvenile NCL (JNCL, CLN3) cases, diagnosed on the basis of age-at-onset, clinical symptomatology, and pathological findings and representing the most common forms of NCL in the United States, and Europe.
A recent study has shown mutations in CLN2 gene, that encodes a novel lysosomal pepstatin-insensitive proteinase (LPIP), in the pathophysiology of late-infantile neuronal ceroid lipofuscinosis (LINCL).
Analysis of archival specimens indicates that several specimens previously classified as LINCL have enzyme activity and thus disease is unlikely to arise from mutations in CLN2.
Classic late-infantile NCL (Jansky-Bielschowsky disease) is caused by mutations in a gene encoding a pepstatin-insensitive lysosomal peptidase (CLN2 on chromosome 11p15), and juvenile-onset NCL (Batten disease) is caused by mutations in a gene encoding a 438-amino-acid membrane protein (CLN3 on chromosome 16p12) of unknown function.
Characterization of endopeptidase activity of tripeptidyl peptidase-I/CLN2 protein which is deficient in classical late infantile neuronal ceroid lipofuscinosis.
Classical late-infantile neuronal ceroid lipofuscinosis (LINCL; CLN2) is an inherited neurodegenerative disorder of childhood characterized by seizures, loss of vision, and progressive motor and mental deterioration.
We identified a novel nonsense CLN2 mutation (Q509X) in three Italian children with classical late-infantile neuronal ceroid lipofuscinosis (LINCL) from two unrelated families.
Late-infantile neuronal ceroid lipofuscinosis (LINCL), an autosomal recessively inherited lysosomal storage disorder characterized by autofluorescent inclusions and rapid progression of neurodegeneration, is due to CLN2 gene mutations.
Treatment of LINCL fibroblasts with recombinant CLN2 protein restores normal enzyme activity and ameliorates accumulation of the major storage protein, mitochondrial ATP synthase subunit c.
Association of the R447H mutation with a delayed onset form of LINCL in two separate families raised the question of whether R447HCLN2 retains residual activity.
Of particular importance was the finding of normal TPP-I activity in two patients who had been diagnosed as having classical late infantile neuronal ceroid lipofuscinosis.
Our laboratory has developed a diagnostic service for classical late infantile neuronal ceroid lipofuscinosis (LINCL) by assay of tripeptidyl-peptidase I (TPP-I) activity using the fluorogenic peptide substrate Ala-Ala-Phe aminomethylcoumarin, followed by a screen for three mutations in the CLN2 gene.
Complementary molecular studies identified mutations in the CLN2 gene in the archival tissues and thereby convincingly demonstrated that these three children truly had classic late infantile neuronal ceroid lipofuscinosis (LINCL), now called CLN2.
An assay for the CLN2p/TPP-I based on the cleavage of amino terminal tripeptide from G-F-F-L-AFC was applied to prenatal and postnatal diagnosis of LINCL patients and heterozygote carriers.