Table of Contents - *115500
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*115500
ICD+
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| CATALASE; CAT | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HGNC Approved Gene Symbol: CAT | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Cytogenetic location: 11p13 Genomic coordinates (GRCh37): 11:34,460,471 - 34,493,606 (from NCBI) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Gene Phenotype Relationships | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Clinical Synopsis | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| TEXT | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Description | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Catalase (EC 1.11.1.6) catalyzes the decomposition of hydrogen peroxide to oxygen and water. Mammalian catalase of approximately 240 kD occurs as a complex of 4 identical subunits, each of which contains 526 amino acid residues (summary by Ogata, 1991; Ogata et al., 2008). | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Cloning | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Bell et al. (1986) gave the cDNA sequence for human kidney catalase. The coding region had 1,581 basepairs. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Gene Structure | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Quan et al. (1986) found that the CAT gene is 34 kb long and split into 13 exons. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Mapping | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Wieacker et al. (1980) assigned a gene for catalase to 11p by study of man-mouse cell hybrid clones. In the hybrid cells, detection of human catalase was precluded by the complexity of the electrophoretic patterns resulting from interference by a catalase-modifying enzyme activity. Therefore, a specific antihuman antibody was used in conjunction with electrophoresis. In mouse, catalase is not syntenic to the beta-globin cluster or to LDH-A. Niikawa et al. (1982) confirmed the close linkage of catalase to the gene of the WAGR complex (see 194070) by demonstrating low levels of catalase activity in the erythrocytes of 2 unrelated patients with the WAGR syndrome and small deletions in 11p. From the study of dosage in 2 unrelated patients with an interstitial deletion involving 11p13, Narahara et al. (1984) concluded that both the catalase locus and the WAGR locus are situated in the chromosome segment 11p1306-p1305, with catalase distal to WAGR. By classic linkage studies using RFLPs of the several genes as markers, Kittur et al. (1985) derived the following sequence of loci: cen--CAT--16 cM--CALC--8 cM--PTH--pter, with the interval between CAT and PTH estimated at 26 cM. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Cytogenetics | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Junien et al. (1980) investigated catalase gene dosage effects in a case of 11p13 deletion, a case of trisomy of all of 11p except 11p13, and a case of trisomy 11p13. The results were consistent with assignment of the catalase locus to 11p13 and its linkage with the WAGR complex (194070). Assay of catalase activity should be useful in identifying those cases of presumed new mutation aniridia that have a risk of Wilms tumor or gonadoblastoma, even in the absence of visible chromosomal deletion. In karyotypically normal patients with aniridia, Wilms tumor, or the combination of the 2, Ferrell and Riccardi (1981) found normal catalase levels. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Biochemical Features | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Several rare electrophoretic variants of red cell catalase were identified by Baur (1963). Nance et al. (1968) also described electrophoretic variants. Kenney et al. (2005) found that keratoconus (see 148300) corneas exhibited a 2.20-fold increase in catalase mRNA and 1.8-fold increase in enzyme activity. They concluded that elevated levels of cathepsins V/L2, B (116810), and G (116830) in keratoconus corneas could stimulate hydrogen peroxide production which, in turn, could upregulate catalase, an antioxidant enzyme. These and other findings supported the hypothesis that keratoconus corneas undergo oxidative stress and tissue degradation. Shibata et al. (1967) found that an immunologically reactive but enzymatically inactive protein about one-sixth the size of active catalase is present in red cells of patients with acatalasemia (614097). | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Molecular Genetics | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Data on gene frequencies of allelic variants were tabulated by Roychoudhury and Nei (1988). Acatalasemia In Japanese patients with acatalasemia (614097), Wen et al. (1990) identified a homozygous splice site mutation in the CAT gene (115500.0001). Goth and Eaton (2000) reported an increased frequency of diabetes in catalase-deficient (hypo/acatalasemic) Hungarian patients as compared with unaffected first-degree relatives and the general Hungarian population. The authors speculated that quantitative deficiency of catalase might predispose to cumulative oxidant damage of pancreatic beta-cells and resulting diabetes. Aniridia Boyd et al. (1986) described a catalase RFLP with 2 different enzymes and used these polymorphisms to exclude deletion of the catalase gene in patients with sporadic aniridia, including one who was known to have a deletion and another suspected of having a deletion. Mannens et al. (1987) found deletion of the catalase locus in 6 of 9 patients with aniridia (AN2; 106210). One of these catalase-deficient aniridia patients had a normal karyotype. No catalase deletion could be demonstrated in 7 Wilms tumors. Hypertension Jiang et al. (2001) found an association between essential hypertension defined as elevation of systolic blood pressure and a single-nucleotide polymorphism (SNP) located 844 bp upstream of the start codon of the CAT gene. The TT phenotype was associated with higher blood pressure than the CC phenotype and CT was intermediate. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Animal Model | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| In the acatalasemic mouse, Shaffer and Preston (1990) demonstrated that a CAG (glutamine)-to-CAT (histidine) transversion in the third position of codon 11 was responsible for the deficiency. To determine the role of reactive oxygen species in mammalian longevity, Schriner et al. (2005) generated transgenic mice that overexpressed human catalase localized to the peroxisome, the nucleus, or mitochondria. Median and maximum life spans were maximally increased (average of 5 months and 5.5 months, respectively) in the mitochondrial catalase-expressing animals. Cardiac pathology and cataract development were delayed, oxidative damage was reduced, peroxide production and peroxide-induced aconitase inactivation were attenuated, and the development of mitochondrial deletions was reduced. Schriner et al. (2005) concluded that their results support the free radical theory of aging and reinforce the importance of mitochondria as a source of these radicals. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ALLELIC VARIANTS (Selected Examples): | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Table View | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| .0001 ACATALASEMIA, JAPANESE TYPE | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| CAT, IVS4, G-A, +5 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| By sequencing the CAT gene for all exons, exon/intron junctions, and 5-prime and 3-prime flanking regions in a case of the Japanese type of acatalasemia (614097), Wen et al. (1990) concluded that the genetic disorder resulted from a splicing mutation, namely, a G-to-A substitution at the fifth position of intron 4. In studies using chimeric genes constructed from the normal or mutant CAT gene and a part of the alpha-globin gene, Wen et al. (1990) showed that when the mutant gene construct was introduced into COS-7 cells, abnormal splicing occurred. The same splice site mutation was found in the genomic DNA of another unrelated acatalasemic person. Kishimoto et al. (1992) found the same mutation in 2 other unrelated Japanese patients and suggested that only a single mutated allele had spread in the Japanese population. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| .0002 ACATALASEMIA, JAPANESE TYPE | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| CAT, 1-BP DEL, 358T | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| In a Japanese individual with acatalasemia (614097), Hirono et al. (1995) identified a homozygous 1-bp deletion (358T) in exon 4 of the CAT gene, causing a frameshift and a premature termination codon. The truncated peptide chain consisted of 133 amino acid residues. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| .0003 ACATALASEMIA, HUNGARIAN TYPE | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| CAT, 2-BP INS, 138GA | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| In a Hungarian patient with acatalasemia (614097), Goth et al. (2000) identified a 138GA insertion in exon 2 of the CAT gene, increasing the GA repeat number from 4 to 5. The insertion caused a frameshift and a premature termination codon. The truncated protein lacks the essential amino acid (histidine 74) in the active center. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| See Also: | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Agar et al. (1986); Feinstein et al. (1966); Kidd et al. (1987); Quan et al. (1985); Schroeder and Saunders (1987) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| REFERENCES | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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