Abstract
Beta-ketothiolase deficiency (mitochondrial acetoacetyl-CoA thiolase (T2) deficiency) is an inherited disease of isoleucine catabolism and ketone body utilization caused by ACAT1 mutations. We identified ten Indian patients who manifested with ketoacidotic episodes of variable severity. The patients showed increased urinary excretion of isoleucine-catabolic intermediates: 2-methyl-3-hydroxybutyrate, 2-methylacetoacetate, and tiglylglycine. Six patients had a favorable outcome, one died, and three developed neurodevelopmental sequela. Mutational analysis revealed a common (p.Met193Arg) and four novel (p.Ile323Thr, p.Ala215Asn, c.1012_1015dup, and c.730+1G>A) ACAT1 mutations. Transient expression analyses of wild-type and mutant cDNA were performed at 30, 37, and 40°C. A p.Ile323Thr mutant T2 was detected with relative enzyme activity and protein amount of 20% and 25%, respectively, compared with wild type at 37°C; it was more prevalent at 30°C but ablated at 40°C. These findings showed that p.Ile323Thr had a significant residual T2 activity with temperature-sensitive instability. Neither residual enzymatic activity nor mutant T2 protein was identified in p.Met193Arg, p.Ala215Asn, and c.1012_1015dup mutations using supernatants; however, these mutant T2 proteins were detected in insoluble pellets by immunoblot analysis. Expression analyses confirmed pathogenicity of these mutations. T2 deficiency has a likely high incidence in India and p.Met193Arg may be a common mutation in the Indian population.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsAbbreviations
- 2MAA:
-
2-Methylacetoacetate
- 2M3HB:
-
2-Methyl-3-hydroxybutyrate
- SCOT:
-
Succinyl-CoA:3-oxoacid CoA transferase
- TIG:
-
Tiglylglycine
- T2:
-
Mitochondrial acetoacetyl-CoA thiolase
References
Abdelkreem E, Otsuka H, Sasai H et al (2016) Beta-ketothiolase deficiency: resolving challenges in diagnosis. J Inborn Errors Metab Screen 4:1–9
Akella RR, Aoyama Y, Mori C, Lingappa L, Cariappa R, Fukao T (2014) Metabolic encephalopathy in beta-ketothiolase deficiency: the first report from India. Brain Dev 36:537–540
Dave Usha P, Das Bibhu R (2010) Newborn screening – from “Guthrie age to Genomic age”. J Obstet Gynaecol India 60:210–214
Finka A, Mattoo RU, Goloubinoff P (2016) Experimental milestones in the discovery of molecular chaperones as polypeptide unfolding enzymes. Annu Rev Biochem 85:715–742
Fukao T, Yamaguchi S, Kano M et al (1990) Molecular cloning and sequence of the complementary DNA encoding human mitochondrial acetoacetyl-coenzyme A thiolase and study of the variant enzymes in cultured fibroblasts from patients with 3-ketothiolase deficiency. J Clin Invest 86:2086–2092
Fukao T, Song XQ, Mitchell GA et al (1997) Enzymes of ketone body utilization in human tissues: protein and messenger RNA levels of succinylcoenzyme A (CoA):3 ketoacid CoA transferase and mitochondrial and cytosolic acetoacetylCoA thiolases. Pediatr Res 42:498–502
Fukao T, Nakamura H, Song XQ et al (1998) Characterization of N93S, I312T, and A333P missense mutations in two Japanese families with mitochondrial acetoacetyl-CoA thiolase deficiency. Hum Mutat 12:245–254
Fukao T, Scriver CR, Kondo N, T2 Collaborative Working Group (2001) The clinical phenotype and outcome of mitochondrial acetoacetyl-CoA thiolase deficiency (beta-ketothiolase or T2 deficiency) in 26 enzymatically proved and mutation-defined patients. Mol Genet Metab 72:109–114
Fukao T, Nakamura H, Nakamura K et al (2002) Characterization of 6 mutations in 5 Spanish patients with mitochondrial acetoacetyl-CoA thiolase deficiency: effects of amino acid substitutions on tertiary structure. Mol Genet Metab 75:235–243
Fukao T, Boneh A, Aoki Y, Kondo N (2008) A novel single-base substitution (c.1124A>G) that activates a 5-base upstream cryptic splice donor site within exon 11 in the human mitochondrial acetoacetyl-CoA thiolase gene. Mol Genet Metab 94:417–421
Fukao T, Nguyen HT, Nguyen NT et al (2010) A common mutation, R208X, identified in Vietnamese patients with mitochondrial acetoacetyl-CoA thiolase (T2) deficiency. Mol Genet Metab 100:37–41
Fukao T, Mitchell G, Sass JO, Hori T, Orii K, Aoyama Y (2014) Ketone body metabolism and its defects. J Inherit Metab Dis 37:541–551
Hori T, Yamaguchi S, Shinkaku H et al (2015) Inborn errors of ketone body utilization. Pediatr Int 57:41–48
Muntau AC, Leandro J, Staudigl M, Mayer F, Gersting SW (2014) Innovative strategies to treat protein misfolding in inborn errors of metabolism: pharmacological chaperones and proteostasis regulators. J Inherit Metab Dis 37:505–523
Niwa H, Yamamura K, Miyazaki J (1991) Efficient selection for high-expression transfectants with a novel eukaryotic vector. Gene 108:193–199
Sakurai S, Fukao T, Haapalainen AM et al (2007) Kinetic and expression analyses of seven novel mutations in mitochondrial acetoacetyl-CoA thiolase (T2): identification of a Km mutant and an analysis of the mutational sites in the structure. Mol Genet Metab 90:370–378
Sarafoglou K, Matern D, Redlinger-Grosse K et al (2011) Siblings with mitochondrial acetoacetyl-CoA thiolase deficiency not identified by newborn screening. Pediatrics 128:e246–e250
Shapiro MB, Senapathy P (1987) RNA splice junctions of different classes of eukaryotes: sequence statistics and functional implications in gene expression. Nucleic Acids Res 15:7155–7174
West JD, Wang Y, Morano KA (2012) Small molecule activators of the heat shock response: chemical properties, molecular targets, and therapeutic promise. Chem Res Toxicol 25:2036–2053
Zhang GX, Fukao T, Rolland MO et al (2004) Mitochondrial acetoacetyl-CoA thiolase (T2) deficiency: T2-deficient patients with “mild” mutation(s) were previously misinterpreted as normal by the coupled assay with tiglyl-CoA. Pediatr Res 56:60–64
Acknowledgments
The authors thank the Cultural Affairs and Missions Sector, Egyptian Ministry of Higher Education, for providing a scholarship to study beta-ketothiolase deficiency. The authors also thank N. Sakaguchi for her indispensable technical assistance.
Funding
This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan [grant numbers 26114708, 24591505, 16K09962, 15K01693]; Health and Labour Science Research Grants for Research on Intractable Diseases from the Ministry of Health, Labour and Welfare of Japan; and the Practical Research Project for Rare/Intractable Diseases from Japan Agency for Medical Research and Development (AMED).
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Additional information
Communicated by: Michael J Bennett, PhD
Appendices
Synopsis
Beta-ketothiolase (T2) deficiency has a likely high incidence in India where p.Met193Arg may be a common mutation.
Compliance with Ethics Guidelines
Conflict of Interest
Toshiyuki Fukao has received a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan [grant numbers 26114708, 24591505, 16K09962]; Health and Labour Science Research Grants for Research on Intractable Diseases from the Ministry of Health, Labour and Welfare of Japan; and the Practical Research Project for Rare/Intractable Diseases from Japan Agency for Medical Research and Development (AMED).
Yuka Aoyama has received a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan [grant number 15K01693].
Elsayed Abdelkreem, Radha Rama Devi Akella, Usha Dave, Sudhir Sane, Hiroki Otsuka, Hideo Sasai, Mina Nakama, Hidenori Ohnishi, Shaimaa Mahmoud, and Mohamed Abd El Aal declare that they have no conflict of interest.
Informed Consent
All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2000. Informed consents were obtained from all patients or their parents for being included in the study.
Details of the Contributions of Individual Authors
Elsayed Abdelkreem, Hiroki Otsuka, Hideo Sasai, Yuka Aoyama, and Mina Nakama collected data, performed mutational and expression analyses, and drafted the first version of the manuscript. Radha Rama Devi Akella, Usha Dave, and Sudhir Sane were involved in clinical management of patients and critically reviewed the manuscript. Hidenori Ohnishi, Shaimaa Mahmoud, and Mohamed Abd El Aal critically reviewed and revised the manuscript, and approved the final version as submitted. Toshiyuki Fukao initiated and supervised this study, reviewed and revised the manuscript, and approved the final version as submitted. All authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work. All authors confirm the absence of previous similar or simultaneous publications.
Rights and permissions
Copyright information
© 2017 Society for the Study of Inborn Errors of Metabolism (SSIEM)
About this chapter
Cite this chapter
Abdelkreem, E. et al. (2017). Clinical and Mutational Characterizations of Ten Indian Patients with Beta-Ketothiolase Deficiency. In: Morava, E., Baumgartner, M., Patterson, M., Rahman, S., Zschocke, J., Peters, V. (eds) JIMD Reports, Volume 35. JIMD Reports, vol 35. Springer, Berlin, Heidelberg. https://doi.org/10.1007/8904_2016_26
Download citation
DOI: https://doi.org/10.1007/8904_2016_26
Received:
Revised:
Accepted:
Published:
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-662-55832-4
Online ISBN: 978-3-662-55833-1
eBook Packages: Biomedical and Life SciencesBiomedical and Life Sciences (R0)