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Clinical and genetic spectrum of AMPD2-related pontocerebellar hypoplasia type 9. Eur J Hum Genet 2018; 26:695-708. [PMID: 29463858 DOI: 10.1038/s41431-018-0098-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 12/28/2017] [Accepted: 01/09/2018] [Indexed: 11/08/2022] Open
Abstract
Pontocerebellar hypoplasia (PCH) represents a group of autosomal-recessive progressive neurodegenerative disorders of prenatal onset. Eleven PCH subtypes are classified according to clinical, neuroimaging and genetic findings. Individuals with PCH type 9 (PCH9) have a unique combination of postnatal microcephaly, hypoplastic cerebellum and pons, and hypoplastic or absent corpus callosum. PCH9 is caused by biallelic variants in AMPD2 encoding adenosine monophosphate deaminase 2; however, a homozygous AMPD2 frameshift variant has recently been reported in two family members with spastic paraplegia type 63 (SPG63). We identified homozygous or compound heterozygous AMPD2 variants in eight PCH-affected individuals from six families. The eight variants likely affect function and comprise one frameshift, one nonsense and six missense variants; seven of which were novel. The main clinical manifestations in the eight new patients and 17 previously reported individuals with biallelic AMPD2 variants were postnatal microcephaly, severe global developmental delay, spasticity, and central visual impairment. Brain imaging data identified hypomyelination, hypoplasia of the cerebellum and pons, atrophy of the cerebral cortex, complete or partial agenesis of the corpus callosum and the "figure 8" shape of the hypoplastic midbrain as consistent features. We broaden the AMPD2-related clinical spectrum by describing one individual without microcephaly and absence of the characteristic "figure 8" shape of the midbrain. The existence of various AMPD2 isoforms with different functions possibly explains the variability in phenotypes associated with AMPD2 variants: variants leaving some of the isoforms intact may cause SPG63, while those affecting all isoforms may result in the severe and early-onset PCH9.
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Marsh APL, Yap P, Tan T, Pope K, White SM, Chong B, Mcgillivray G, Boys A, Stephenson SEM, Leventer RJ, Stark Z, Lockhart PJ. A novel AMPD2 mutation outside the AMP deaminase domain causes pontocerebellar hypoplasia type 9. Am J Med Genet A 2017; 173:820-823. [PMID: 28168832 DOI: 10.1002/ajmg.a.38076] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 11/15/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Ashley P L Marsh
- Bruce Lefroy Centre For Genetic Health Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia
| | - Patrick Yap
- Victorian Clinical Genetics Services, Murdoch Childrens Research Institute, Parkville, Victoria, Australia.,Genetic Health Service New Zealand (Northern Hub), Auckland City Hospital, Auckland, New Zealand
| | - Tiong Tan
- Victorian Clinical Genetics Services, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
| | - Kate Pope
- Bruce Lefroy Centre For Genetic Health Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Susan M White
- Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia.,Victorian Clinical Genetics Services, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
| | - Belinda Chong
- Victorian Clinical Genetics Services, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
| | - George Mcgillivray
- Victorian Clinical Genetics Services, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
| | - Amber Boys
- Victorian Clinical Genetics Services, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
| | - Sarah E M Stephenson
- Bruce Lefroy Centre For Genetic Health Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia
| | - Richard J Leventer
- Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia.,Neuroscience Research Group, Murdoch Childrens Research Institute, Parkville, Victoria, Australia.,Department of Neurology, University of Melbourne, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Zornitza Stark
- Victorian Clinical Genetics Services, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
| | - Paul J Lockhart
- Bruce Lefroy Centre For Genetic Health Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia
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Toyama K, Morisaki H, Cheng J, Kawachi H, Shimizu F, Ikawa M, Okabe M, Morisaki T. Proteinuria in AMPD2-deficient mice. Genes Cells 2013; 17:28-38. [PMID: 22212473 DOI: 10.1111/j.1365-2443.2011.01568.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The AMPD2 gene, a member of the AMPD gene family encoding AMP deaminase, is widely expressed in nonmuscle tissues including kidney, although its functions have not been fully elucidated. In this study, we studied the function of the AMPD2 gene by establishing AMPD2-deficient model animal. We established AMPD2 knockout mice by using gene transfer and homologous recombination in murine ES cells and studied phenotypes and functions in the kidneys of these animals. AMPD activity was decreased from 22.9 mIU/mg protein to 2.5 mIU/mg protein in the kidneys of AMPD knockout mice. In addition to changes in nucleotide metabolism in the kidneys, proteinuria was found in 3-week-old AMPD2 knockout mice, followed by a further increment up to a peak level at 6 weeks old (up to 0.6 g/dL). The major protein component in the urine of AMPD2 knockout mice was found to be albumin, indicating that AMPD2 may have a key role in glomerular filtration. Indeed, an ultrastructure study of glomerulus specimens from these mice showed effacement of the podocyte foot processes, resembling minimal-change nephropathy in humans. Based on our results, we concluded that AMPD2 deficiency induces imbalanced nucleotide metabolism and proteinuria, probably due to podocyte dysfunction.
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Affiliation(s)
- Keiko Toyama
- Department of Bioscience and Genetics, National Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan
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Cheng J, Morisaki H, Toyama K, Ikawa M, Okabe M, Morisaki T. AMPD3-deficient mice exhibit increased erythrocyte ATP levels but anemia not improved due to PK deficiency. Genes Cells 2012; 17:913-22. [PMID: 23078545 DOI: 10.1111/gtc.12006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Accepted: 08/27/2012] [Indexed: 11/27/2022]
Abstract
AMP deaminase (AMPD) catalyzes AMP to IMP and plays an important role in energy charge and nucleotide metabolism. Human AMPD3 deficiency is a type of erythrocyte-specific enzyme deficiency found in individuals without clinical symptoms, although an increased level of ATP in erythrocytes has been reported. To better understand the physiological and pathological roles of AMPD3 deficiency, we established a line of AMPD3-deficient [A3(-/-)] mice. No AMPD activity and a high level of ATP were observed in erythrocytes of these mice, similar to human RBC-AMPD3 deficiency, while other characteristics were unremarkable. Next, we created AMPD3 and pyruvate kinase (PK) double-deficient [PKA(-/-,-/-)] mice by mating A3(-/-) mice with CBA-Pk-1slc/Pk-1slc mice [PK(-/-)], a spontaneous PK-deficient strain showing hemolytic anemia. In PKA(-/-,-/-) mice, the level of ATP in red blood cells was increased 1.5 times as compared to PK(-/-) mice, although hemolytic anemia in those animals was not improved. In addition, we observed osmotic fragility of erythrocytes in A3(-/-) mice under fasting conditions. In contrast, the ATP level in erythrocytes was elevated in A3(-/-) mice as compared to the control. In conclusion, AMPD3 deficiency increases the level of ATP in erythrocytes, but does not improve anemia due to PK deficiency and leads to erythrocyte dysfunction.
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Affiliation(s)
- Jidong Cheng
- Department of Bioscience and Genetics, National Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan
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Plaideau C, Liu J, Hartleib-Geschwindner J, Bastin-Coyette L, Bontemps F, Oscarsson J, Hue L, Rider MH. Overexpression of AMP-metabolizing enzymes controls adenine nucleotide levels and AMPK activation in HEK293T cells. FASEB J 2012; 26:2685-94. [PMID: 22415305 DOI: 10.1096/fj.11-198168] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We investigated whether overexpression of AMP-metabolizing enzymes in intact cells would modulate oligomycin-induced AMPK activation. Human embryonic kidney (HEK) 293T cells were transiently transfected with increasing amounts of plasmid vectors to obtain a graded increase in overexpression of AMP-deaminase (AMPD) 1, AMPD2, and soluble 5'-nucleotidase IA (cN-IA) for measurements of AMPK activation and total intracellular adenine nucleotide levels induced by oligomycin treatment. Overexpression of AMPD1 and AMPD2 slightly decreased AMP levels and oligomycin-induced AMPK activation. Increased overexpression of cN-IA led to reductions in the oligomycin-induced increases in AMP and ADP concentrations by ∼70 and 50%, respectively, concomitant with a 50% decrease in AMPK activation. The results support the view that a rise in ADP as well as AMP is important for activation of AMPK, which can thus be regulated by the adenylate energy charge. The control coefficient of cN-IA on AMP was 0.3-0.7, whereas the values for AMPD1 and AMPD2 were <0.1, suggesting that in this model cN-IA exerts a large proportion of control over intracellular AMP. Therefore, small molecule inhibition of cN-IA could be a strategy for AMPK activation.
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Affiliation(s)
- Catheline Plaideau
- Université Catholique de Louvain and de Duve Institute, Brussels, Belgium
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Pacheco-Aguilar R, Ocano-Higuera VM, Ezquerra-Brauer JM, Castillo-Yañez FJ, García-Sánchez G, Marquez-Rios † E. Partial characterization of 5′-nucleotidase from giant squid ( Dosidicus gigas) mantle Caracterización parcial de la enzima 5′-nucleotidasa del manto de calamar gigante ( Dosidicus gigas). CYTA - JOURNAL OF FOOD 2010. [DOI: 10.1080/19476330903145981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Pacheco-Aguilar R, Ezquerra-Brauer JM, Castillo-Yañez J, Lugo-Sanchez ME, Marquez-Rios E. Partial Characterization of AMP Deaminase from Jumbo Squid (Dosidicus gigas) Mantle. JOURNAL OF AQUATIC FOOD PRODUCT TECHNOLOGY 2009. [DOI: 10.1080/10498850903225692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Marotta R, Parry BR, Shain DH. Divergence of AMP Deaminase in the Ice Worm Mesenchytraeus solifugus (Annelida, Clitellata, Enchytraeidae). INTERNATIONAL JOURNAL OF EVOLUTIONARY BIOLOGY 2009; 2010:715086. [PMID: 21350654 PMCID: PMC3042610 DOI: 10.4061/2009/715086] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Accepted: 05/22/2009] [Indexed: 11/20/2022]
Abstract
Glacier ice worms, Mesenchytraeus solifugus and related species, are the largest glacially obligate metazoans. As one component of cold temperature adaptation, ice worms maintain atypically high energy levels in an apparent mechanism to offset cold temperature-induced lethargy and death. To explore this observation at a mechanistic level, we considered the putative contribution of 5' adenosine monophosphate deaminase (AMPD), a key regulator of energy metabolism in eukaryotes. We cloned cDNAs encoding ice worm AMPD, generating a fragment encoding 543 amino acids that included a short N-terminal region and complete C-terminal catalytic domain. The predicted ice worm AMPD amino acid sequence displayed conservation with homologues from other mesophilic eukaryotes with notable exceptions. In particular, an ice worm-specific K188E substitution proximal to the AMP binding site likely alters the architecture of the active site and negatively affects the enzyme's activity. Paradoxically, this would contribute to elevated intracellular ATP levels, which appears to be a signature of cold adapted taxa.
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Affiliation(s)
- Roberto Marotta
- Department of Biology, University of Milano, via Celoria 26, 20133 Milano, Italy
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Szydlowska M, Chodorowski Z, Rybakowska I, Nagel-Starczynowska G, Kaletha K. Full-size form of human liver AMP-deaminase? Mol Cell Biochem 2005; 266:133-7. [PMID: 15646034 DOI: 10.1023/b:mcbi.0000049150.19623.e8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
AMP-deaminase from human liver was purified by two-step phosphocellulose chromatography, and SDS-PAG electrophoresis of the most active enzyme fraction eluted has been performed. The largest of the protein fragments revealed had a size (92 kDa) of an apparent full-size enzyme subunit, and reacted positively with antibodies produced against specific human ampd2 gene product. Three-day storage at cold room temperature modified significantly the electrophoretical pattern of the enzyme, evidencing continuous and progressive degradation of its structure. This is a first report evidencing the presence of apparent full-size form of human liver AMP-deaminase in preparation obtained from endogenous source.
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Affiliation(s)
- M Szydlowska
- Department of Biochemistry, Medical University of Gdansk, Debinki, Gdansk, Poland.
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