Alternative titles; symbols
HGNC Approved Gene Symbol: PRKCG
SNOMEDCT: 719210007;
Cytogenetic location: 19q13.42 Genomic coordinates (GRCh38): 19:53,881,094-53,907,652 (from NCBI)
| Location | Phenotype |
Phenotype MIM number |
Inheritance |
Phenotype mapping key |
|---|---|---|---|---|
| 19q13.42 | Spinocerebellar ataxia 14 | 605361 | Autosomal dominant | 3 |
PRKCG is a member of the protein kinase C (PKC) gene family (see Coussens et al., 1986 and PRKCA; 176960).
Asai et al. (2009) noted that the PRKCG gene contains 18 exons.
See 176960 for evidence that the PRKCG gene is located on 19q13.2-q13.4. Johnson et al. (1988) identified an informative RFLP in the PKCC gene, with the PIC value of 0.62, identified with the enzyme MspI.
By fluorescence in situ hybridization, Trask et al. (1993) assigned the PRKCG gene to 19q13.4. Because of the simultaneous mapping of a very large number of probes to chromosome 19, they were able to arrive at a finer localization of specific genes than was possible when one or a few probes were mapped.
Saunders and Seldin (1990) showed that the mouse homolog of PKCC, which they symbolized Prkcg, is located on chromosome 7, as is also the murine equivalent of CKMM (123310) and ERCC2 (126340).
Asai et al. (2009) transfected human neuroblastoma SH-SY5Y cells with wildtype and mutant PRKCG in a medium L-buthionine-(S,R)-sulfoximine (BSO), an oxidative stress inducer, and showed hypersensitivity in mutant PRKCG expressing cells, which was correlated with increase kinase activity. Aprataxin (APTX; 606350), a DNA repair protein causative for autosomal recessive ataxia, was found to be a preferential substrate of mutant PRKCG, and phosphorylation inhibited its nuclear entry. The phosphorylation of APTX at thr111, located adjacent to the nuclear localization signal, disturbed interactions with importin-alpha (KPNA2; 600685), thus inhibiting nuclear import. Decreased nuclear APTX increased oxidative stress-induced DNA damage and cell death.
In an affected member of a family with spinocerebellar ataxia-14 (SCA14; 605361) described by Brkanac et al. (2002) and in 2 of 39 unrelated patients with ataxia not attributable to trinucleotide expansions, Chen et al. (2003) identified 3 different mutations in the PRKCG gene, each of which resulted in a nonconservative missense mutation in a highly conserved residue in C1, the cysteine-rich region of the protein (176980.0001-176980.0003). Structural modeling predicted that the first and third of these amino acid substitutions would severely abrogate the zinc-binding or phorbol ester-binding capabilities of the protein. Immunohistochemical studies on cerebellar tissue from an affected member of the previously described SCA14 family demonstrated reduced staining for both PKC-gamma and ataxin-1 (ATX1; 601556) in Purkinje cells, whereas staining for calbindin (114050) was preserved. The results suggested that there may be a common pathway for PKC-gamma-related and polyglutamine-related neurodegeneration.
Chen et al. (2005) identified 3 different mutations in the PRKCG gene (see, e.g., 176980.0007) in 3 of 270 unrelated patients with spinocerebellar ataxia. Two additional unrelated patients had a possible splice site mutation. The authors noted that most of the mutations in PRKCG reported in SCA14 have occurred in the regulatory domain of the protein, suggesting that it is important in Purkinje cell function.
Among 284 index cases of French or German origin with autosomal dominant cerebellar ataxia (ADCA), Klebe et al. (2005) identified 6 different mutations, including 5 novel mutations, in the PRKCG gene in 15 affected members from 6 French families. Combined with a previous study (Stevanin et al., 2004), SCA14 represented 1.5% (7 of 454) of French families with ADCA.
In a family with SCA14, Asai et al. (2009) identified a 102-bp deletion beginning at the termination codon in exon 18 of the PRKCG gene (176980.0009). The proband had early onset of a severe phenotype and was homozygous for the deletion, whereas a paternal grandmother had late onset and was heterozygous for the deletion. The parent's were unrelated and asymptomatic, but declined genetic testing, though were assumed to be obligate carriers.
Najmabadi et al. (2011) performed homozygosity mapping followed by exon enrichment and next-generation sequencing in 136 consanguineous families (over 90% Iranian and less than 10% Turkish or Arab) segregating syndromic or nonsyndromic forms of autosomal recessive intellectual disability. In 2 separate consanguineous families segregating spinocerebellar ataxia-14 (605361), they identified a frameshift mutation and a missense mutation, respectively, in the PRKCG gene (176980.0010, 176980.0011).
Alonso et al. (2005) noted that mutations identified in the regulatory domain of the PRKCG gene are associated with a relatively pure form of SCA14 beginning in the third or fourth decade of life. In contrast, mutations in the PRKCG catalytic domain are associated with a broader age at onset, ranging from childhood to the sixth decade, and with cognitive impairment in some cases (see, e.g., 176980.0006 and Stevanin et al., 2004; 176980.0007 and Chen et al., 2005)
The curly tail mutant mouse provides a model of folate-resistant neural tube defects (NTD; 608317), in which defects can be prevented by inositol therapy in early pregnancy. Cogram et al. (2004) investigated the molecular mechanism by which inositol prevents mouse NTDs. They examined neurulation-stage embryos for PKC expression and applied PKC inhibitors to curly tail embryos developing in culture. Application of peptide inhibitors to neurulation-stage embryos revealed an absolute dependence on the activity of PRKCB1 (176970) and PRKCG for prevention of NTDs by inositol, and partial dependence on PRKCZ (176982), whereas PRKCA, PRKCB2 (see 176970), PRKCD (176977), and PRKCE (176975) were dispensable. Defective proliferation of hindgut cells was a key component of the pathogenic sequence leading to NTDs in curly tail. Hindgut cell proliferation was stimulated specifically by inositol, an effect that required activation of PRKCB1. Cogram et al. (2004) proposed an essential role for PRKCB1 and PRKCG in mediating the prevention of mouse NTDs by inositol.
Because the PRKCG gene encodes a form of protein kinase C that is expressed in the retina and because it maps to the region of 19q where a form of retinitis pigmentosa, RP11 (600138), maps, PRKCG was considered a candidate gene for RP11. Al-Maghtheh et al. (1998) described 2 families with RP11-linked dominant RP in which a missense change (arg659-to-ser) in the PRKCG gene cosegregated with the disease. However, they failed to discover a mutation in PRKCG in 3 other families with reduced penetrance showing linkage to this region. Reduced penetrance is a characteristic of RP11: some carriers develop RP that is symptomatic at an age before 20 years, whereas others are asymptomatic and show no funduscopic or electroretinographic signs even at ages beyond 70 years. Dryja et al. (1999) analyzed the PRKCG gene in 3 families with dominant RP with reduced penetrance in which McGee et al. (1997) found linkage data pointing to RP11 as the cause of RP in these families. None of the patients had a defect in codon 659. Furthermore, none of the patients had an abnormality in the coding region or the flanking intron splice-acceptor or -donor sites, except for one patient who was heterozygous for a silent change in codon 24: GCT (ala) to GCC (ala). Vithana et al. (2001) stated that the PRKCG gene is not involved in RP11. They subsequently identified mutations in the PRP31 gene (606419) that were responsible for RP11.
In affected members of a family segregating spinocerebellar ataxia-14 (SCA14; 605361) reported by Brkanac et al. (2002), Chen et al. (2003) identified a 301C-T transition in exon 4 of the PRKCG gene, predicting a substitution of hydrophilic tyrosine for hydrophobic histidine at codon 101 (his101 to tyr; H101Y).
In a woman with spinocerebellar ataxia-14 (SCA14; 605361) and her affected son and daughter, Chen et al. (2003) identified a 355T-C transition in exon 4 of the PRKCG gene, resulting in a ser119-to-pro (S119P) mutation. The mean age at onset was 42 years (range, 35 to 51 years).
In a 55-year-old man with onset of spinocerebellar ataxia-14 (SCA14; 605361) in his early twenties and no family history of ataxia, Chen et al. (2003) identified a 383G-A transition in exon 4 of the PRKCG gene, resulting in a gly128-to-asp (G128D) mutation. His father and mother had died at ages 83 and 54 years, respectively.
Morita et al. (2006) identified heterozygosity for the G128D mutation in a Japanese woman with slowly progressive pure SCA14. Gait difficulties began at age 42 years. By age 62, she was still ambulatory with mild ataxia, saccadic pursuit, scanning speech, and cerebellar atrophy, but no other abnormalities. There was no family history of the disorder.
In affected members of a large Dutch family with autosomal dominant spinocerebellar ataxia-14 (SCA14; 605361), van de Warrenburg et al. (2003) identified a 353G-A transition in exon 4 of the PRKCG gene, resulting in a gly118-to-asp (G118D) substitution. Two unaffected members also carried the mutation. The G118D mutation occurs in the conserved C1 regulatory domain of the protein.
Verbeek et al. (2005) identified the G118D mutation in 8 additional Dutch patients with SCA14. Three were sibs, and the other 5 were independent referrals. Haplotype analysis indicated a founder effect. Genealogic analysis of these 8 patients and the patients reported by van de Warrenburg et al. (2003) showed that they all derived from a common ancestor from the Dutch province of North Brabant who was born in 1722. Some of the patients exhibited mild extrapyramidal symptoms.
By functional expression studies in COS-7 cells, Verbeek et al. (2005) demonstrated that the G118D mutation increased the intrinsic kinase activity of PRKCG and caused more rapid translocation of the protein to the plasma membrane in response to calcium influx.
In all 11 affected members of a Japanese family with spinocerebellar ataxia-14 (SCA14; 605361), Yabe et al. (2003) identified a 380A-G transition in exon 4 of the PRKCG gene, resulting in a gln127-to-arg (Q127R) substitution. Two unaffected family members carried the mutation, indicating reduced penetrance of the disorder.
In affected members of a French family with spinocerebellar ataxia-14 (SCA14; 605361), Stevanin et al. (2004) identified a heterozygous T-to-C transition in exon 18 of the PRKCG gene, resulting in a phe643-to-leu (F643L) substitution in a highly conserved region of the catalytic domain (C4) of the protein. In addition to cerebellar ataxia, many family members demonstrated cognitive deficits and depression. The mutation was not identified in 410 control chromosomes.
In 4 affected members of a family with spinocerebellar ataxia-14 (SCA14; 605361), Chen et al. (2005) identified a heterozygous 1081A-G transition in exon 10 of the PRKCG gene, resulting in a ser361-to-gly (S361G) substitution in a highly conserved region of the catalytic domain of the protein. The mutation was not identified in 384 control chromosomes. Age at disease onset in this family ranged from 5 to 60 years of age, and depression was a feature.
In affected members of a Portuguese family with slowly progressive, uncomplicated spinocerebellar ataxia-14 (SCA14; 605361), Alonso et al. (2005) identified a heterozygous 303C-G transversion in exon 4 of the PRKCG gene, resulting in a his101-to-gln (H101Q) substitution in a highly conserved region of the C1 domain of the protein. Functional expression studies showed that the H101Q mutation resulted in significant downregulation of protein levels. Both wildtype and mutant mRNA levels were similar, and the reduction in protein levels occurred over time, indicating that the mutant protein is putatively targeted for degradation at a higher rate. Thus, the H101Q mutation likely affects protein stability and may lead to loss of protein kinase activity by changing Zn(2+) interaction and phorbol ester-binding. The H101Q mutation was not present in 400 control chromosomes.
In a family with spinocerebellar ataxia-14 (SCA14; 605361), Asai et al. (2009) identified heterozygosity for a 102-bp deletion at the termination codon in exon 18, resulting in a met697-to-ile (M697I) substitution and a C-terminal extension of 13 amino acids (M697Iex). The deletion was not identified in 200 control individuals. The 20-year-old female proband was homozygous for the deletion and developed progressive cerebellar ataxia at age 7 years and generalized truncal and limb myoclonus at age 18 years. Brain MRI at age 16 years showed cerebellar atrophy. Her 86-year-old paternal grandmother was heterozygous and had progressive ataxia without myoclonus starting at age 60 years, and her maternal grandmother had late-onset Parkinsonism and died at 78 years. The proband's parents were unrelated and asymptomatic, but declined genetic testing, though were assumed to be obligate carriers. The M697Iex mutant protein showed increased kinase activity compared to wildtype.
In family 8600273, Najmabadi et al. (2011) identified homozygosity for a deletion of 1,717 nucleotides in the PRKCG gene at genomic coordinate Chr19:59086740-59088457 (NCBI36), causing a frameshift at codon 177 (val177fs), in 3 sibs with moderate intellectual disability, ataxia, and progressive cerebellar atrophy (SCA14; 605361). The parents were first cousins and had 3 healthy sibs.
In family M146, Najmabadi et al. (2011) identified homozygosity for an asp480-to-tyr (D480Y) substitution in the PRKCG gene in 2 sibs with moderate intellectual disability and ataxia (SCA14; 605361). The parents were first cousins and had 2 healthy children.
Al-Maghtheh, M., Vithana, E. N., Inglehearn, C. F., Moore, T., Bird, A. C., Bhattacharya, S. S. Segregation of a PRKCG mutation in two RP11 families. (Letter) Am. J. Hum. Genet. 62: 1248-1252, 1998. [PubMed: 9545390] [Full Text: https://doi.org/10.1086/301819]
Alonso, I., Costa, C., Gomes, A., Ferro, A., Seixas, A. I., Silva, S., Cruz, V. T., Coutinho, P., Sequeiros, J., Silveira, I. A novel H101Q mutation causes PKC-gamma loss in spinocerebellar ataxia type 14. J. Hum. Genet. 50: 523-529, 2005. [PubMed: 16189624] [Full Text: https://doi.org/10.1007/s10038-005-0287-z]
Asai, H., Hirano, M., Shimada, K., Kiriyama, T., Furiya, Y., Ikeda, M., Iwamoto, T., Mori, T., Nishinaka, K., Konishi, N., Udaka, F., Ueno, S. Protein kinase C-gamma, a protein causative for dominant ataxia, negatively regulates nuclear import of recessive-ataxia-related aprataxin. Hum. Molec. Genet. 18: 3533-3543, 2009. [PubMed: 19561170] [Full Text: https://doi.org/10.1093/hmg/ddp298]
Brkanac, Z., Bylenok, L., Fernandez, M., Matsushita, M., Lipe, H., Wolff, J., Nochlin, D., Raskind, W. H., Bird, T. D. A new dominant spinocerebellar ataxia linked to chromosome 19q13.4-qter. Arch. Neurol. 59: 1291-1295, 2002. Note: Erratum: Arch. Neurol.: 59: 1972 only, 2002. [PubMed: 12164726] [Full Text: https://doi.org/10.1001/archneur.59.8.1291]
Chen, D.-H., Brkanac, Z., Verlinde, C. L. M. J., Tan, X.-J., Bylenok, L., Nochlin, D., Matsushita, M., Lipe, H., Wolff, J., Fernandez, M., Cimino, P. J., Bird, T. D., Raskind, W. H. Missense mutations in the regulatory domain of PKC-gamma: a new mechanism for dominant nonepisodic cerebellar ataxia. Am. J. Hum. Genet. 72: 839-849, 2003. [PubMed: 12644968] [Full Text: https://doi.org/10.1086/373883]
Chen, D.-H., Cimino, P. J., Ranum, L. P. W., Zoghbi, H. Y., Yabe, I., Schut, L., Margolis, R. L., Lipe, H. P., Feleke, A., Matsushita, M., Wolff, J., Morgan, C., Lau, D., Fernandez, M., Sasaki, H., Raskind, W. H., Bird, T. D. The clinical and genetic spectrum of spinocerebellar ataxia 14. Neurology 64: 1258-1260, 2005. [PubMed: 15824357] [Full Text: https://doi.org/10.1212/01.WNL.0000156801.64549.6B]
Cogram, P., Hynes, A., Dunlevy, L. P. E., Greene, N. D. E., Copp, A. J. Specific isoforms of protein kinase C are essential for prevention of folate-resistant neural tube defects by inositol. Hum. Molec. Genet. 13: 7-14, 2004. [PubMed: 14613966] [Full Text: https://doi.org/10.1093/hmg/ddh003]
Coussens, L., Parker, P. J., Rhee, L., Yang-Feng, T. L., Chen, E., Waterfield, M. D., Francke, U., Ullrich, A. Multiple, distinct forms of bovine and human protein kinase C suggest diversity in cellular signaling pathways. Science 233: 859-866, 1986. [PubMed: 3755548] [Full Text: https://doi.org/10.1126/science.3755548]
Dryja, T. P., McEvoy, J., McGee, T. L., Berson, E. L. No mutations in the coding region of the PRKCG gene in three families with retinitis pigmentosa linked to the RP11 locus on chromosome 19q. (Letter) Am. J. Hum. Genet. 65: 926-928, 1999. [PubMed: 10441600] [Full Text: https://doi.org/10.1086/302554]
Johnson, K. J., Jones, P. J., Spurr, N., Nimmo, E., Davies, J., Creed, H., Weiss, M., Williamson, R. Linkage relationships of the protein kinase C gamma gene which exclude it as a candidate for myotonic dystrophy. Cytogenet. Cell Genet. 48: 13-15, 1988. [PubMed: 2460293] [Full Text: https://doi.org/10.1159/000132577]
Klebe, S., Durr, A., Rentschler, A., Hahn-Barma, V., Abele, M., Bouslam, N., Schols, L., Jedynak, P., Forlani, S., Denis, E., Dussert, C., Agid, Y., Bauer, P., Globas, C., Wullner, U., Brice, A., Riess, O., Stevanin, G. New mutations in protein kinase C gamma associated with spinocerebellar ataxia type 14. Ann. Neurol. 58: 720-729, 2005. [PubMed: 16193476] [Full Text: https://doi.org/10.1002/ana.20628]
McGee, T. L., Devoto, M., Ott, J., Berson, E. L., Dryja, T. P. Evidence that the penetrance of mutations at the RP11 locus causing dominant retinitis pigmentosa is influenced by a gene linked to the homologous RP11 allele. Am. J. Hum. Genet. 61: 1059-1066, 1997. [PubMed: 9345108] [Full Text: https://doi.org/10.1086/301614]
Morita, H., Yoshida, K., Suzuki, K., Ikeda, S. A Japanese case of SCA14 with the gly128asp mutation. J. Hum. Genet. 51: 1118-1121, 2006. [PubMed: 17024314] [Full Text: https://doi.org/10.1007/s10038-006-0063-8]
Najmabadi, H., Hu, H., Garshasbi, M., Zemojtel, T., Abedini, S. S., Chen, W., Hosseini, M., Behjati, F., Haas, S., Jamali, P., Zecha, A., Mohseni, M., and 33 others. Deep sequencing reveals 50 novel genes for recessive cognitive disorders. Nature 478: 57-63, 2011. [PubMed: 21937992] [Full Text: https://doi.org/10.1038/nature10423]
Saunders, A. M., Seldin, M. F. The syntenic relationship of proximal mouse chromosome 7 and the myotonic dystrophy gene region on human chromosome 19q. Genomics 6: 324-332, 1990. [PubMed: 2307474] [Full Text: https://doi.org/10.1016/0888-7543(90)90573-d]
Stevanin, G., Hahn, V., Lohmann, E., Bouslam, N., Gouttard, M., Soumphonphakdy, C., Welter, M.-L., Ollagnon-Roman, E., Lemainque, A., Ruberg, M., Brice, A., Durr, A. Mutation in the catalytic domain of protein kinase C gamma and extension of the phenotype associated with spinocerebellar ataxia type 14. Arch. Neurol. 61: 1242-1248, 2004. [PubMed: 15313841] [Full Text: https://doi.org/10.1001/archneur.61.8.1242]
Trask, B., Fertitta, A., Christensen, M., Youngblom, J., Bergmann, A., Copeland, A., de Jong, P., Mohrenweiser, H., Olsen, A., Carrano, A., Tynan, K. Fluorescence in situ hybridization mapping of human chromosome 19: cytogenetic band location of 540 cosmids and 70 genes or DNA markers. Genomics 15: 133-145, 1993. [PubMed: 8432525] [Full Text: https://doi.org/10.1006/geno.1993.1021]
van de Warrenburg, B. P. C., Verbeek, D. S., Piersma, S. J., Hennekam, F. A. M., Pearson, P. L., Knoers, N. V. A. M., Kremer, H. P. H., Sinke, R. J. Identification of a novel SCA14 mutation in a Dutch autosomal dominant cerebellar ataxia family. Neurology 61: 1760-1765, 2003. [PubMed: 14694043] [Full Text: https://doi.org/10.1212/01.wnl.0000098883.79421.73]
Verbeek, D. S., Knight, M. A., Harmison, G. G., Fischbeck, K. H., Howell, B. W. Protein kinase C gamma mutations in spinocerebellar ataxia 14 increase kinase activity and alter membrane targeting. Brain 128: 436-442, 2005. [PubMed: 15618281] [Full Text: https://doi.org/10.1093/brain/awh378]
Verbeek, D. S., van de Warrenburg, B. P. C., Hennekam, F. A. M., Dooijes, D., Ippel, P. F., Verschuuren-Bemelmans, C. C., Kremer, H. P. H., Sinke, R. J. Gly118asp is a SCA14 founder mutation in the Dutch ataxia population. Hum. Genet. 117: 88-91, 2005. [PubMed: 15841389] [Full Text: https://doi.org/10.1007/s00439-005-1278-z]
Vithana, E. N., Abu-Safieh, L., Allen, M. J., Carey, A., Papaioannou, M., Chakarova, C., Al-Maghtheh, M., Ebenezer, N. D., Willis, C., Moore, A. T., Bird, A. C., Hunt, D. M., Bhattacharya, S. S. A human homolog of yeast pre-mRNA splicing gene, PRP31, underlies autosomal dominant retinitis pigmentosa on chromosome 19q13.4 (RP11). Molec. Cell 8: 375-381, 2001. [PubMed: 11545739] [Full Text: https://doi.org/10.1016/s1097-2765(01)00305-7]
Yabe, I., Sasaki, H., Chen, D.-H., Raskind, W. H., Bird, T. D., Yamashita, I., Tsuji, S., Kikuchi, S., Tashiro, K. Spinocerebellar ataxia type 14 caused by a mutation in protein kinase C gamma. Arch. Neurol. 60: 1749-1751, 2003. [PubMed: 14676051] [Full Text: https://doi.org/10.1001/archneur.60.12.1749]