Alternative titles; symbols
HGNC Approved Gene Symbol: PPT1
Cytogenetic location: 1p34.2 Genomic coordinates (GRCh38): 1:40,071,461-40,097,252 (from NCBI)
| Location | Phenotype |
Phenotype MIM number |
Inheritance |
Phenotype mapping key |
|---|---|---|---|---|
| 1p34.2 | Ceroid lipofuscinosis, neuronal, 1 | 256730 | Autosomal recessive | 3 |
Palmitoyl-protein thioesterase (PPT; EC 3.1.2.22) is a small glycoprotein that removes palmitate groups from cysteine residues in lipid-modified proteins. PPT is thought to be involved in the catabolism of lipid-modified proteins (Camp et al., 1994).
Schriner et al. (1996) reported the sequence of the human PPT cDNA and the structure of the human PPT gene. The cDNA predicted a 306-amino acid polypeptide that contains a 25-amino acid signal peptide, 3 N-linked glycosylation sites, and consensus motifs characteristic of thioesterases. Northern blot analysis revealed ubiquitous expression of a single 2.5-kb mRNA, with highest expression in lung, brain, and heart.
Schriner et al. (1996) determined that the human PPT gene spans 27 kb and contains 8 coding exons and a large ninth exon containing the entire 3-prime untranslated region of 1,388 bp. An Alu repeat and promoter elements corresponding to putative binding sites for several general transcription factors were identified in the 1,060 nucleotides upstream of the transcription start site.
Heinonen et al. (2000) analyzed the intracellular processing and localization of adenovirus-mediated Ppt in mouse primary neurons and in nerve growth factor (see 162030)-induced PC12 cells. The neuronal processing of Ppt was found to be similar to that observed in peripheral cells, and a significant amount of the PPT enzyme was secreted in the primary neurons. Immunofluorescence analysis of the neuronal cells infected with wildtype Ppt showed a granular staining pattern in the cell soma and neuronal shafts. Interestingly, Ppt was also found in the synaptic ends of the neuronal cells, and the staining pattern of the enzyme colocalized to a significant extent with the synaptic markers SV2 (185860) and synaptophysin (313475). Heinonen et al. (2000) found that their in vitro data corresponded with the distribution of endogenous Ppt in mouse brain and suggested that Ppt may not solely be a lysosomal hydrolase. Heinonen et al. (2000) suggested that the specific targeting of Ppt into the neuritic shafts and nerve terminals indicates that Ppt may be associated with the maintenance of synaptic function, and speculated that the enzyme could have an extracellular substrate as well.
Lehtovirta et al. (2001) determined the neuronal localization of PPT by confocal microscopy, cryoimmunoelectron microscopy, and cell fractionation. In mouse primary neurons and brain tissue, PPT was localized in synaptosomes and synaptic vesicles but not in lysosomes. Furthermore, in polarized epithelial Caco-2 cells, PPT was localized exclusively to the basolateral site, in contrast to the classic lysosomal enzyme aspartylglucosaminidase (AGA; 613228), which is localized in the apical site. The authors hypothesized that PPT has a role outside the lysosomes in the brain and may be associated with synaptic functioning.
The genes PPT1 and CLN2 (607998), which are mutant in neuronal ceroid lipofuscinosis-1 (CLN1; 256730) and CLN2 (204500), respectively, encode lysosomal enzymes; the CLN3 (607042) and CLN5 (608102) genes, which are mutant in CLN3 (204200) and CLN5, respectively, encode membrane-spanning proteins. Zhong et al. (2000) addressed the question of why deficiencies of lysosomal enzymes and membrane-spanning proteins produce similar clinical phenotypes and pathologic changes. They hypothesized that CLN-encoded proteins may comprise a functional pathogenic pathway in which protein associations play important roles. To test this hypothesis, they studied protein-protein interactions among the PPT1-, CLN2-, and CLN3-encoded proteins using a yeast 2-hybrid system. Results provided no evidence that CLN-encoded proteins interact with each other.
Crystal Structure
Bellizzi et al. (2000) determined the crystal structure of PPT1 with and without bound palmitate by using multiwavelength anomalous diffraction phasing. The structure revealed an alpha/beta-hydrolase fold with a catalytic triad composed of ser115-his289-asp233 and provided insight into the structural basis for the phenotypes associated with PPT1 mutations.
Vesa et al. (1995) mapped the PPT1 gene to chromosome 1p32 by fluorescence in situ hybridization and showed that it is located 70 kb telomeric to the 5-prime end of a rearranged LMYC gene (164850). From these results and findings of pulsed-field gel electrophoresis, the authors assigned the PPT1 gene to the site of a CpG island identified in the critical region to which the locus for neuronal ceroid lipofuscinosis-1 had been mapped.
By direct sequencing of PPT1 cDNA derived from brain RNA of 2 Finnish patients with infantile-onset CLN1, Vesa et al. (1995) identified a homozygous mutation in the PPT1 gene (R122W; 600722.0001). The homozygous mutation was identified in all patients from 40 of 42 Finnish families, consistent with a founder effect.
Mitchison et al. (1998) identified homozygous or compound heterozygous mutations in the PPT1 gene (600722.0002-600722.0006) in 11 patients with juvenile-onset CLN1 with the ultrastructural findings of granular osmiophilic deposits. A T75P mutation (600722.0002) accounted for 9 of the 22 disease chromosomes analyzed; R151X (600722.0006) accounted for 7.
Mole et al. (1999) tabulated the reported mutations in the PPT1 gene associated with CLN1.
Das et al. (1998) identified mutations in the PPT1 gene in 29 of 32 unrelated U.S. and Canadian families with PPT1 deficiency. The R151X substitution accounted for 40% of the alleles and was associated with severe disease in the homozygous state. The T75P substitution accounted for 13% of the alleles and was associated with a later onset and protracted clinical course. A total of 19 different mutations were found, resulting in a broader spectrum of clinical presentations than previously seen in the Finnish population. Symptoms first appeared at ages ranging from 3 months to 9 years, and about half of the subjects survived into the second or even third decade of life.
Das et al. (2001) assessed the biochemical impact of PPT mutations through the study of cells derived from patients and from the expression of recombinant PPT enzymes in COS and Sf9 cells. All missense mutations associated with infantile-onset CLN1 showed no residual enzyme activity, whereas mutations associated with late-onset phenotypes showed up to 2% residual activity. Two mutations increased the Km of the enzyme for palmitoylated substrates and were located in positions that would distort the palmitate-binding pocket. An initiator methionine mutation in 2 late-onset patients was expressed at a significant level in COS cells, suggesting that the mutant codon may be utilized to a clinically important extent in vivo. The most common PPT nonsense mutation, R151X, was associated with an absence of PPT mRNA. Mannose 6-phosphate modification of wildtype and mutant PPT enzymes was grossly normal at the level of the phosphotransferase reaction. However, mutant PPT enzymes did not bind to mannose 6-phosphate receptors (see 154540) in a blotting assay. This observation was related to the failure of the mutant expressed enzymes to gain access to 'uncovering enzyme' (N-acetylglucosamine-1-phosphodiester alpha-N-acetyl glucosaminidase), presumably due to a block in transit out of the endoplasmic reticulum, where mutant enzymes are degraded.
Gupta et al. (2001) engineered disruptions in the Ppt1 and Ppt2 (603298) genes to create knockout mice that were deficient in either enzyme. Both lines of mice were viable and fertile; however, both lines developed spasticity (a 'clasping' phenotype) at a median age of 21 weeks and 29 weeks, respectively. Motor abnormalities progressed in the Ppt1 knockout mice, leading to death by 10 months of age. In contrast, most Ppt2 mice were alive at 12 months. Myoclonic jerking and seizures were prominent in the Ppt1 mice. Autofluorescent storage material was striking throughout the brains of both strains of mice. Neuronal loss and apoptosis were particularly prominent in Ppt1-deficient brains. These studies provided a mouse model for infantile neuronal ceroid lipofuscinosis and further suggested that PPT2 serves a role in the brain that is not carried out by PPT1.
Zhang et al. (2006) reported that the brains of Ppt1-null mice accumulated autofluorescent material, abnormalities of the neuronal endoplasmic reticulum (ER), and showed progressive apoptosis that correlated with neurologic motor impairment. There was an abnormal accumulation of palmitoylated GAP43 (162060) in the ER. Increased levels of this and other S-acylated proteins coincided with activation of the unfolded protein response, characterized by increased phosphorylation of EIF2A (609234) and activation of caspases, which ultimately leads to cellular apoptosis. Zhang et al. (2006) concluded that PPT1 deficiency leads to neurodegeneration by activation of the unfolded protein response as a result of abnormal accumulation of palmitoylated proteins.
Zhang et al. (2007) noted that the brains of Ppt1-null mice showed increased recruitment of phagocytic cells to remove apoptotic cells. These mice showed an age-dependent increased production of lysophosphatidylcholine (LPC), which was catalyzed by the activation of cytosolic phospholipase A2 (PLA2G4A; 600522). LPC acted as a lipid signal for phagocyte recruitment. These findings elucidate a mechanism for phagocyte infiltration that may contribute to neuropathology.
Neural communication relies on repeated cycles of exo- and endocytosis of synaptic vesicles containing neurotransmitters at the plasma membranes of nerve terminals. In the mouse brain, Kim et al. (2008) found that Ppt1 localized in the synaptosomes and synaptic vesicles of the presynaptic compartment under physiologic conditions. Ppt1 deficiency resulted in abnormal and persistent membrane retention of palmitoylated synaptic vesicle-associated proteins, including VAMP2 (185881), SNAP25 (600322), syntaxin-1 (STX1A; 186590), SYTI (185605), and GAD65 (138275) in brain tissue from both human patients with neuronal lipofuscinosis and Ppt1-deficient mice. Since these S-acylated proteins must undergo depalmitoylation to detach from the membrane, which is required for recycling, Ppt1 deficiency may cause these proteins to remain membrane bound. Kim et al. (2008) proposed a mechanism by which PPT1 deficiency leads to the disruption of synaptic vesicle recycling, prevents the regeneration of fresh vesicles, and results in a progressive decline in the total pool size, which ultimately impairs neurotransmission.
Kielar et al. (2009) reported a progressive breakdown of axons and synapses in the brains of 2 different mouse models of NCL: the Ppt1-null mouse model of infantile NCL and Cln6 (606725)-deficient mouse model (nclf) of late infantile NCL (CLN6; 601780). Synaptic pathology was evident in the thalamus and cortex of these mice, but occurred much earlier within the thalamus. Quantitative comparisons of expression levels for a subset of proteins previously implicated in regulation of axonal and synaptic vulnerability revealed changes in proteins involved with synaptic function/stability and cell-cycle regulation in both strains of NCL mice. Protein expression changes were present at pre/early-symptomatic stages, occurring in advance of morphologically detectable synaptic or axonal pathology and again displayed regional selectivity, occurring first within the thalamus and only later in the cortex. Although significant differences in individual protein expression profiles existed between the 2 NCL models studied, 2 of the 15 proteins examined Vdac1 (604492) and Pttg1 (604147) displayed robust and significant changes at pre/early-symptomatic time-points in both strains of NCL mice. Kielar et al. (2009) concluded that synapses and axons are important early pathologic targets in the NCLs.
Sanders et al. (2010) reported a 9-month-old Miniature Dachshund that presented with NCL-like signs, including disorientation, ataxia, weakness, visual impairment, and behavioral changes. The dog was euthanized at 14 months of age due to the severity of neurologic signs. Microscopic analysis of neurons of retina, cerebellum, and cerebral cortex revealed ultrastructural changes characteristic of classical infantile NCL. Sequencing of the Ppt1 gene from the affected dog revealed a homozygous 1-nucleotide insertion (C) after nucleotide 736 in exon 8, upstream of the codon for the active site, his289. Brain tissue from this dog lacked Ppt1 activity. The sire and dam of the propositus were heterozygous for the mutation, whereas 127 unrelated Dachshunds were homozygous for the wildtype allele.
Miller et al. (2015) generated a transgenic mouse model homozygous for the common R151X PPT1 mutation (600722.0006). The phenotype of the mutant mice recapitulated that observed in humans, including impaired motor function, decreased exploratory behavior, accumulation of autofluorescent material in the brain, and widespread astrogliosis and microglial activation throughout the brain. Administration of the read-through compound ataluren (PTC124) increased PPT1 enzyme activity and protein level in mutant mice in a proof-of-principle study.
In patients with classic infantile-onset CLN1 (256730) from 40 of 42 Finnish families, Vesa et al. (1995) identified a homozygous 364A-T transversion in the PPT1 gene, resulting in an arg122-to-trp (R122W) substitution. Unaffected parents were heterozygous for the mutation. The arg122 residue is immediately adjacent to a lipase consensus sequence that contains the putative active-site serine of the protein. A heterozygous R122W substitution was identified in 3 of 200 control Finnish individuals, yielding a carrier frequency of 1 in 70. The findings were consistent with 1 major disease-causing mutation in the Finnish population resulting from a founder effect. In the remaining 2 Finnish families, patients were compound heterozygous for R122W and an uncharacterized null allele. Two of 17 non-Finnish patients, 1 German and 1 Estonian, were also homozygous for R122W. In vitro functional expression studies showed that the R122W mutant protein was retained in the endoplasmic reticulum, was not secreted, and had undetectable enzyme activity.
Mitchison et al. (1998) found that a thr75-to-pro (T75P) missense mutation in the PPT1 gene accounted for 9 of 22 disease chromosomes in 11 patients with juvenile-onset CLN1 (256730). In 1 of the 11 patients the T75P was homozygous; in 7 others it was present in compound heterozygous state with a nonsense mutation, either arg151-to-ter (R151X; 600722.0006) or leu10-to-ter (L10X; 600722.0005).
In 29 U.S. and Canadian families with PPT1 deficiency, Das et al. (1998) found that the T75P mutation accounted for 13% of the alleles and was associated with a late onset and protracted clinical course.
In 1 of 22 disease chromosomes from 11 patients with juvenile-onset CLN1 (256730), Mitchison et al. (1998) identified an asp79-to-gly (D79G) missense mutation in the PPT1 gene. It was present in compound heterozygous state with the R151X mutation (600722.0006).
In 1 of 22 disease chromosomes from 11 patients with juvenile-onset CLN1 (256730), Mitchison et al. (1998) found a leu219-to-gln (L219Q) substitution of the PPT gene. It was found in compound heterozygous state with the R151X mutation (600722.0006).
In 2 of 22 disease chromosomes from 11 patients with juvenile-onset CLN1 (256730), Mitchison et al. (1998) identified a leu10-to-ter (L10X) nonsense mutation in the PPT1 gene. In each case it was present in compound heterozygous state with a missense mutation.
In 7 of 22 disease chromosomes from 11 patients with juvenile-onset CLN1 (256730), Mitchison et al. (1998) found an arg151-to-ter (R151X) nonsense mutation in the PPT1 gene. In each case it was found in compound heterozygous state with a missense mutation.
In 29 U.S. and Canadian families with PPT1 deficiency, Das et al. (1998) demonstrated that the R151X mutation accounted for 40% of the alleles and was associated with severe disease in homozygous state.
See also 600722.0009 and van Diggelen et al. (2001), and 600722.0010 and Ramadan et al. (2007).
Miller et al. (2015) generated a transgenic mouse model homozygous for the common R151X PPT1 mutation. Mutant PPT1 was significantly decreased in multiples tissues, consistent with nonsense-mediated mRNA decay, and PPT1 enzyme activity in homozygous mice was 1.7 to 3.1% of controls. The phenotype of the mutant mice recapitulated that observed in humans, including impaired motor function, decreased exploratory behavior, accumulation of autofluorescent material in the brain, and widespread astrogliosis and microglial activation throughout the brain. Intraperitoneal injection of the read-through drug ataluren (PTC124) increased PPT1 enzyme activity and protein levels in the liver, but not in the brain. Higher dosages of ataluren resulted in increased PPT1 activity in the brain, but caused a paradoxical decrease of PPT1 activity in the liver. The study provided proof of principle of the potential use of read-through drugs in the treatment of the disorder resulting from this specific mutation.
In a 4-year-old boy with infantile-onset CLN1 (256730), Santorelli et al. (1998) identified a single adenine insertion at nucleotide position 169 (160insA) in the PPT gene. The mutation was homozygous in the proband, heterozygous in his healthy parents, and not found in control alleles. The mutation led to an early stop codon, resulting in an abnormal and truncated PPT protein. The 4-year-old boy developed normally until the age of 12 months. He could sit and crawl; however, he never achieved independent walking. Psychomotor regression occurred over the subsequent 2 months. At age 14 months, he had lost most of his motor abilities and showed a progressive worsening of his clinical status. At approximately 18 months of age, he was hypotonic and also presented severe speech impairment, visual loss, and myoclonic seizures. Electroretinogram and visual evoked potentials were altered. MRI showed severe cerebral cortical atrophy with relative sparing of the cerebellum. Ultrastructural studies showed recurrent granular osmiophilic deposits in both endothelial cells and fibroblasts on skin biopsy.
De Vries et al. (1999) reported the first prenatal diagnosis of CLN1 (256730). The fetus was found to be homozygous for a 451C-T substitution in the PPT1 gene, resulting in premature termination of the protein after 150 amino acids. The mutation gives rise to loss of a TaqI restriction site.
In 2 sisters with adult-onset CLN1 (256730), van Diggelen et al. (2001) identified compound heterozygosity for mutations in the PPT1 gene: R151X (600722.0006) and a G-C change in exon 3, resulting in a gly108-to-arg (G108R) substitution. Onset in both patients was in the thirties, with symptoms of depression progressing to cognitive decline, cerebellar ataxia, parkinsonism, and decreased verbal fluency in their fifties. Both patients showed generalized brain atrophy on MRI. Enzyme analysis showed severe PPT deficiency.
In a 24-year-old woman with adult-onset CLN1 (256730), Ramadan et al. (2007) identified compound heterozygosity for 2 mutations in the PPT1 gene: a 134A-G transition, resulting in a cys45-to-tyr (C45Y) substitution, and R151X (600722.0006). The patient presented with psychiatric symptoms, including low mood, irritability, lack of interest, bizarre behavior, and academic decline. She deteriorated over the next 18 months, developing tunnel vision, retinitis pigmentosa, visual hallucinations, and further cognitive decline. Brain MRI showed marked generalized cerebral and cerebellar atrophy. Biochemical studies showed decreased PPT1 activity.
Bellizzi, J. J., III, Widom, J., Kemp, C., Lu, J.-Y., Das, A. K., Hofmann, S. L., Clardy, J. The crystal structure of palmitoyl protein thioesterase 1 and the molecular basis of infantile neuronal ceroid lipofuscinosis. Proc. Nat. Acad. Sci. 97: 4573-4578, 2000. [PubMed: 10781062] [Full Text: https://doi.org/10.1073/pnas.080508097]
Camp, L. A., Verkruyse, L. A., Afendis, S. J., Slaughter, C. A., Hofmann, S. L. Molecular cloning and expression of palmitoyl-protein thioesterase. J. Biol. Chem. 269: 23212-23219, 1994. [PubMed: 7916016]
Das, A. K., Becerra, C. H. R., Yi, W., Lu, J.-Y., Siakotos, A. N., Wisniewski, K. E., Hofmann, S. L. Molecular genetics of palmitoyl-protein thioesterase deficiency in the U.S. J. Clin. Invest. 102: 361-370, 1998. [PubMed: 9664077] [Full Text: https://doi.org/10.1172/JCI3112]
Das, A. K., Lu, J.-Y., Hofmann, S. L. Biochemical analysis of mutations in palmitoyl-protein thioesterase causing infantile and late-onset forms of neuronal ceroid lipofuscinosis. Hum. Molec. Genet. 10: 1431-1439, 2001. [PubMed: 11440996] [Full Text: https://doi.org/10.1093/hmg/10.13.1431]
de Vries, B. B. A., Kleijer, W. J., Keulemans, J. L. M., Voznyi, Y. V., Franken, P. F., Eurlings, M. C. M., Galjaard, R. J., Losekoot, M., Catsman-Berrevoets, C. E., Breuning, M. H., Taschner, P. E. M., van Diggelen, O. P. First-trimester diagnosis of infantile neuronal ceroid lipofuscinosis (INCL) using PPT enzyme assay and CLN1 mutation analysis. Prenatal Diag. 19: 559-562, 1999. [PubMed: 10416973]
Gupta, P., Soyombo, A. A., Atashband, A., Wisniewski, K. E., Shelton, J. M., Richardson, J. A., Hammer, R. E., Hofmann, S. L. Disruption of PPT1 or PPT2 causes neuronal ceroid lipofuscinosis in knockout mice. Proc. Nat. Acad. Sci. 98: 13566-13571, 2001. [PubMed: 11717424] [Full Text: https://doi.org/10.1073/pnas.251485198]
Heinonen, O., Kyttala, A., Lehmus, E., Paunio, T., Peltonen, L., Jalanko, A. Expression of palmitoyl protein thioesterase in neurons. Molec. Genet. Metab. 69: 123-129, 2000. [PubMed: 10720439] [Full Text: https://doi.org/10.1006/mgme.2000.2961]
Kielar, C., Wishart, T. M., Palmer, A., Dihanich, S., Wong, A. M., Macauley, S. L., Chan, C.-H., Sands, M. S., Pearce, D. A., Cooper, J. D., Gillingwater, T. H. Molecular correlates of axonal and synaptic pathology in mouse models of Batten disease. Hum. Molec. Genet. 18: 4066-4080, 2009. [PubMed: 19640925] [Full Text: https://doi.org/10.1093/hmg/ddp355]
Kim, S.-J., Zhang, Z., Sarkar, C., Tsai, P.-C., Lee, Y.-C., Dye, L., Mukherjkee, A. B. Palmitoyl protein thioesterase-1 deficiency impairs synaptic vesicle recycling at nerve terminals, contributing to neuropathology in humans and mice. J. Clin. Invest. 118: 3075-3086, 2008. [PubMed: 18704195] [Full Text: https://doi.org/10.1172/JCI33482]
Lehtovirta, M., Kyttala, A., Eskelinen, E.-L., Hess, M., Heinonen, O., Jalanko, A. Palmitoyl protein thioesterase (PPT) localizes into synaptosomes and synaptic vesicles in neurons: implications for infantile neuronal ceroid lipofuscinosis (INCL). Hum. Molec. Genet. 10: 69-75, 2001. [PubMed: 11136716] [Full Text: https://doi.org/10.1093/hmg/10.1.69]
Miller, J. N., Kovacs, A. D., Pearce, D. A. The novel Cln1(R151X) mouse model of infantile neuronal ceroid lipofuscinosis (INCL) for testing nonsense suppression therapy. Hum. Molec. Genet. 24: 185-196, 2015. [PubMed: 25205113] [Full Text: https://doi.org/10.1093/hmg/ddu428]
Mitchison, H. M., Hofmann, S. L., Becerra, C. H. R., Munroe, P. B., Lake, B. D., Crow, Y. J., Stephenson, J. B. P., Williams, R. E., Hofman, I. L., Taschner, P. E. M., Martin, J.-J., Philippart, M., Andermann, E., Andermann, F., Mole, S. E., Gardiner, R. M., O'Rawe, A. M. Mutations in the palmitoyl-protein thioesterase gene (PPT; CLN1) causing juvenile neuronal ceroid lipofuscinosis with granular osmiophilic deposits. Hum. Molec. Genet. 7: 291-297, 1998. Note: Erratum: Hum. Molec. Genet. 7: 765 only, 1998. [PubMed: 9425237] [Full Text: https://doi.org/10.1093/hmg/7.2.291]
Mole, S. E., Mitchison, H. M., Munroe, P. B. Molecular basis of the neuronal ceroid lipofuscinoses: mutations in CLN1, CLN2, CLN3, and CLN5. Hum. Mutat. 14: 199-215, 1999. [PubMed: 10477428] [Full Text: https://doi.org/10.1002/(SICI)1098-1004(1999)14:3<199::AID-HUMU3>3.0.CO;2-A]
Ramadan, H., Al-Din, A. S., Ismail, A., Balen, F., Varma, A., Twomey, A., Watts, R., Jackson, M., Anderson, G., Green, E., Mole, S. E. Adult neuronal ceroid lipofuscinosis caused by deficiency in palmitoyl protein thioesterase 1. Neurology 68: 387-388, 2007. [PubMed: 17261688] [Full Text: https://doi.org/10.1212/01.wnl.0000252825.85947.2f]
Sanders, D. N., Farias, F. H., Johnson, G. S., Chiang, V., Cook, J. R., O'Brien, D. P., Hofmann, S. L., Lu, J.-Y., Katz, M. L. A mutation in canine PPT1 causes early onset neuronal ceroid lipofuscinosis in a Dachshund. Molec. Genet. Metab. 100: 349-356, 2010. [PubMed: 20494602] [Full Text: https://doi.org/10.1016/j.ymgme.2010.04.009]
Santorelli, F. M., Bertini, E., Petruzzella, V., Di Capua, M., Calvieri, S., Gasparini, P., Zeviani, M. A novel insertion mutation (A169i) in the CLN1 gene is associated with infantile neuronal ceroid lipofuscinosis in an Italian patient. Biochem. Biophys. Res. Commun. 245: 519-522, 1998. [PubMed: 9571187] [Full Text: https://doi.org/10.1006/bbrc.1998.8484]
Schriner, J. E., Yi, W., Hofmann, S. L. cDNA and genomic cloning of human palmitoyl-protein thioesterase (PPT), the enzyme defective in infantile neuronal ceroid lipofuscinosis. Genomics 34: 317-322, 1996. Note: Erratum: Genomics 38: 458 only, 1996. [PubMed: 8786130] [Full Text: https://doi.org/10.1006/geno.1996.0292]
van Diggelen, O. P., Thobois, S., Tilikete, C., Zabot, M.-T., Keulemans, J. L. M., van Bunderen, P. A., Taschner, P. E. M., Losekoot, M., Voznyi, Y. V. Adult neuronal ceroid lipofuscinosis with palmitoyl-protein thioesterase deficiency: first adult-onset patients of a childhood disease. Ann. Neurol. 50: 269-272, 2001. [PubMed: 11506414] [Full Text: https://doi.org/10.1002/ana.1103]
Vesa, J., Hellsten, E., Verkruyse, L. A., Camp, L. A., Rapola, J., Santavuori, P., Hofmann, S. L., Peltonen, L. Mutations in the palmitoyl protein thioesterase gene causing infantile neuronal ceroid lipofuscinosis. Nature 376: 584-588, 1995. [PubMed: 7637805] [Full Text: https://doi.org/10.1038/376584a0]
Zhang, Z., Lee, Y.-C., Kim, S.-J., Choi, M. S., Tsai, P.-C., Saha, A., Wei, H., Xu, Y., Xiao, Y.-J., Zhang, P., Heffer, A., Mukherjee, A. B. Production of lysophosphatidylcholine by cPLA2 in the brain of mice lacking PPT1 is a signal for phagocyte infiltration. Hum. Molec. Genet. 16: 837-847, 2007. [PubMed: 17341491] [Full Text: https://doi.org/10.1093/hmg/ddm029]
Zhang, Z., Lee, Y.-C., Kim, S.-J., Choi, M. S., Tsai, P.-C., Xu, Y., Xiao, Y.-J., Zhang, P., Heffer, A., Mukherjee, A. B. Palmitoyl-protein thioesterase-1 deficiency mediates the activation of the unfolded protein response and neuronal apoptosis in INCL. Hum. Molec. Genet. 15: 337-346, 2006. [PubMed: 16368712] [Full Text: https://doi.org/10.1093/hmg/ddi451]
Zhong, N. A., Moroziewicz, D. N., Ju, W., Wisniewski, K. E., Jurkiewicz, A., Brown, W. T. CLN-encoded proteins do not interact with each other. Neurogenetics 3: 41-44, 2000. [PubMed: 11085596] [Full Text: https://doi.org/10.1007/pl00022978]