1
|
Demetriou K, Nisbet J, Coman D, Ewing AD, Phillips L, Smith S, Lipke M, Inwood A, Spicer J, Atthow C, Wilgen U, Robertson T, McWhinney A, Swenson R, Espley B, Snowdon B, McGill JJ, Summers KM. Molecular genetic analysis of candidate genes for glutaric aciduria type II in a cohort of patients from Queensland, Australia. Mol Genet Metab 2024; 142:108516. [PMID: 38941880 DOI: 10.1016/j.ymgme.2024.108516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 06/11/2024] [Accepted: 06/14/2024] [Indexed: 06/30/2024]
Abstract
Glutaric aciduria type II (GAII) is a heterogeneous genetic disorder affecting mitochondrial fatty acid, amino acid and choline oxidation. Clinical manifestations vary across the lifespan and onset may occur at any time from the early neonatal period to advanced adulthood. Historically, some patients, in particular those with late onset disease, have experienced significant benefit from riboflavin supplementation. GAII has been considered an autosomal recessive condition caused by pathogenic variants in the gene encoding electron-transfer flavoprotein ubiquinone-oxidoreductase (ETFDH) or in the genes encoding electron-transfer flavoprotein subunits A and B (ETFA and ETFB respectively). Variants in genes involved in riboflavin metabolism have also been reported. However, in some patients, molecular analysis has failed to reveal diagnostic molecular results. In this study, we report the outcome of molecular analysis in 28 Australian patients across the lifespan, 10 paediatric and 18 adult, who had a diagnosis of glutaric aciduria type II based on both clinical and biochemical parameters. Whole genome sequencing was performed on 26 of the patients and two neonatal onset patients had targeted sequencing of candidate genes. The two patients who had targeted sequencing had biallelic pathogenic variants (in ETFA and ETFDH). None of the 26 patients whose whole genome was sequenced had biallelic variants in any of the primary candidate genes. Interestingly, nine of these patients (34.6%) had a monoallelic pathogenic or likely pathogenic variant in a single primary candidate gene and one patient (3.9%) had a monoallelic pathogenic or likely pathogenic variant in two separate genes within the same pathway. The frequencies of the damaging variants within ETFDH and FAD transporter gene SLC25A32 were significantly higher than expected when compared to the corresponding allele frequencies in the general population. The remaining 16 patients (61.5%) had no pathogenic or likely pathogenic variants in the candidate genes. Ten (56%) of the 18 adult patients were taking the selective serotonin reuptake inhibitor antidepressant sertraline, which has been shown to produce a GAII phenotype, and another two adults (11%) were taking a serotonin-norepinephrine reuptake inhibitor antidepressant, venlafaxine or duloxetine, which have a mechanism of action overlapping that of sertraline. Riboflavin deficiency can also mimic both the clinical and biochemical phenotype of GAII. Several patients on these antidepressants showed an initial response to riboflavin but then that response waned. These results suggest that the GAII phenotype can result from a complex interaction between monoallelic variants and the cellular environment. Whole genome or targeted gene panel analysis may not provide a clear molecular diagnosis.
Collapse
Affiliation(s)
- Kalliope Demetriou
- Queensland Lifespan Metabolic Medicine Service, Queensland Children's Hospital, South Brisbane, QLD 4101, Australia
| | - Janelle Nisbet
- Queensland Lifespan Metabolic Medicine Service, Mater Hospital Brisbane, South Brisbane, QLD 4101, Australia
| | - David Coman
- Queensland Lifespan Metabolic Medicine Service, Mater Hospital Brisbane, South Brisbane, QLD 4101, Australia; Wesley Medical Centre, Auchenflower, QLD 4066, Australia; University of Queensland, St Lucia, QLD 4072, Australia
| | - Adam D Ewing
- Mater Research Institute-University of Queensland, Translational Research Institute, 37 Kent St, Woolloongabba, QLD 4102, Australia
| | - Liza Phillips
- Queensland Lifespan Metabolic Medicine Service, Mater Hospital Brisbane, South Brisbane, QLD 4101, Australia
| | - Sally Smith
- Queensland Lifespan Metabolic Medicine Service, Queensland Children's Hospital, South Brisbane, QLD 4101, Australia; Queensland Lifespan Metabolic Medicine Service, Mater Hospital Brisbane, South Brisbane, QLD 4101, Australia
| | - Michelle Lipke
- Queensland Lifespan Metabolic Medicine Service, Queensland Children's Hospital, South Brisbane, QLD 4101, Australia; Queensland Lifespan Metabolic Medicine Service, Mater Hospital Brisbane, South Brisbane, QLD 4101, Australia
| | - Anita Inwood
- Queensland Lifespan Metabolic Medicine Service, Queensland Children's Hospital, South Brisbane, QLD 4101, Australia; Queensland Lifespan Metabolic Medicine Service, Mater Hospital Brisbane, South Brisbane, QLD 4101, Australia; University of Queensland, St Lucia, QLD 4072, Australia
| | - Janette Spicer
- Queensland Lifespan Metabolic Medicine Service, Queensland Children's Hospital, South Brisbane, QLD 4101, Australia
| | - Catherine Atthow
- Queensland Lifespan Metabolic Medicine Service, Queensland Children's Hospital, South Brisbane, QLD 4101, Australia
| | - Urs Wilgen
- University of Queensland, St Lucia, QLD 4072, Australia; Chemical Pathology, Pathology Queensland, Royal Brisbane and Women's Hospital, Herston, QLD 4029, Australia
| | - Thomas Robertson
- University of Queensland, St Lucia, QLD 4072, Australia; Anatomical Pathology, Pathology Queensland, Royal Brisbane and Women's Hospital, Herston, QLD 4029, Australia
| | - Avis McWhinney
- Chemical Pathology, Mater Pathology, Mater Hospital, Mater Hospital Brisbane, QLD 4101, Australia
| | - Rebecca Swenson
- Chemical Pathology, Pathology Queensland, Royal Brisbane and Women's Hospital, Herston, QLD 4029, Australia
| | - Brayden Espley
- Chemical Pathology, Pathology Queensland, Royal Brisbane and Women's Hospital, Herston, QLD 4029, Australia
| | - Brianna Snowdon
- Chemical Pathology, Pathology Queensland, Royal Brisbane and Women's Hospital, Herston, QLD 4029, Australia
| | - James J McGill
- Queensland Lifespan Metabolic Medicine Service, Queensland Children's Hospital, South Brisbane, QLD 4101, Australia; Queensland Lifespan Metabolic Medicine Service, Mater Hospital Brisbane, South Brisbane, QLD 4101, Australia; Chemical Pathology, Pathology Queensland, Royal Brisbane and Women's Hospital, Herston, QLD 4029, Australia; Chemical Pathology, Mater Pathology, Mater Hospital, Mater Hospital Brisbane, QLD 4101, Australia
| | - Kim M Summers
- Mater Research Institute-University of Queensland, Translational Research Institute, 37 Kent St, Woolloongabba, QLD 4102, Australia.
| |
Collapse
|
2
|
Prasun P, Evans A, Cork E, Houten SM, Webb BD. A novel deleterious ETFA promoter variant causative of multiple acyl-CoA dehydrogenase deficiency. Am J Med Genet A 2023; 191:1089-1093. [PMID: 36579410 DOI: 10.1002/ajmg.a.63104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 12/08/2022] [Accepted: 12/10/2022] [Indexed: 12/30/2022]
Abstract
Multiple acyl-CoA dehydrogenase deficiency (MADD) is an autosomal recessive disorder of fatty acid, amino acid, and choline metabolism. We describe a patient identified through newborn screening in which the diagnosis of MADD was confirmed based on metabolic profiling, but clinical molecular sequencing of ETFA, ETFB, and ETFDH was normal. In order to identify the genetic etiology of MADD, we performed whole genome sequencing and identified a novel homozygous promoter variant in ETFA (c.-85G > A). Subsequent studies showed decreased ETFA protein expression in lymphoblasts. A promoter luciferase assay confirmed decreased activity of the mutant promoter. In both assays, the variant displayed considerable residual activity, therefore we speculate that our patient may have a late onset form of MADD (Type III). Our findings may be helpful in establishing a molecular diagnosis in other MADD patients with a characteristic biochemical profile but apparently normal molecular studies.
Collapse
Affiliation(s)
- Pankaj Prasun
- Department of Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Anthony Evans
- Department of Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Emalyn Cork
- Department of Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Sander M Houten
- Department of Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Bryn D Webb
- Department of Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Division of Genetics and Metabolism, Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| |
Collapse
|
4
|
Tummolo A, Leone P, Tolomeo M, Solito R, Mattiuzzo M, Lepri FR, Lorè T, Cardinali R, De Giovanni D, Simonetti S, Barile M. Combined
isobutyryl‐CoA
and multiple
acyl‐CoA
dehydrogenase deficiency in a boy with altered riboflavin homeostasis. JIMD Rep 2022; 63:276-291. [PMID: 35822092 PMCID: PMC9259400 DOI: 10.1002/jmd2.12292] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 04/07/2022] [Accepted: 04/12/2022] [Indexed: 11/24/2022] Open
Abstract
In this report, we describe the case of an 11‐year‐old boy, who came to our attention for myalgia and muscle weakness, associated with inappetence and vomiting. Hypertransaminasemia was also noted, with ultrasound evidence of hepatomegaly. Biochemical investigations revealed acylcarnitine and organic acid profiles resembling those seen in MADD, that is, multiple acyl‐CoA dehydrogenase deficiencies (OMIM #231680) a rare inherited disorder of fatty acids, amino acids, and choline metabolism. The patient carried a single pathogenetic variant in the ETFDH gene (c.524G>A, p.Arg175His) and no pathogenetic variant in the riboflavin (Rf) homeostasis related genes (SLC52A1, SLC52A2, SLC52A3, SLC25A32, FLAD1). Instead, compound heterozygosity was found in the ACAD8 gene (c.512C>G, p.Ser171Cys; c.822C>A, p.Asn274Lys), coding for isobutyryl‐CoA dehydrogenase (IBD), whose pathogenic variants are associated to IBD deficiency (OMIM #611283), a rare autosomal recessive disorder of valine catabolism. The c.822C>A was never previously described in a patient. Subsequent further analyses of Rf homeostasis showed reduced levels of flavins in plasma and altered FAD‐dependent enzymatic activities in erythrocytes, as well as a significant reduction in the level of the plasma membrane Rf transporter 2 in erythrocytes. The observed Rf/flavin scarcity in this patient, possibly associated with a decreased ETF:QO efficiency might be responsible for the observed MADD‐like phenotype. The patient's clinical picture improved after supplementation of Rf, l‐carnitine, Coenzyme Q10, and also 3OH‐butyrate. This report demonstrates that, even in the absence of genetic defects in genes involved in Rf homeostasis, further targeted molecular analysis may reveal secondary and possibly treatable biochemical alterations in this pattern.
Collapse
Affiliation(s)
- Albina Tummolo
- Metabolic Diseases and Clinical Genetics Unit Children's Hospital “Giovanni XXIII” Bari Italy
| | - Piero Leone
- Department of Biosciences, Biotechnology and Biopharmaceutics University of Bari “A. Moro” Bari Italy
| | - Maria Tolomeo
- Department of Biosciences, Biotechnology and Biopharmaceutics University of Bari “A. Moro” Bari Italy
| | - Rita Solito
- Department of Biosciences, Biotechnology and Biopharmaceutics University of Bari “A. Moro” Bari Italy
| | - Matteo Mattiuzzo
- Laboratory of Medical Genetics Translational Cytogenomics Research Unit, Bambino Gesù Children Hospital Rome Italy
| | - Francesca Romana Lepri
- Laboratory of Medical Genetics Translational Cytogenomics Research Unit, Bambino Gesù Children Hospital Rome Italy
| | - Tania Lorè
- Regional Centre for Neonatal Screening Children's Hospital “Giovanni XXIII” Bari Italy
| | - Roberta Cardinali
- Regional Centre for Neonatal Screening Children's Hospital “Giovanni XXIII” Bari Italy
| | - Donatella De Giovanni
- Metabolic Diseases and Clinical Genetics Unit Children's Hospital “Giovanni XXIII” Bari Italy
| | - Simonetta Simonetti
- Regional Centre for Neonatal Screening Children's Hospital “Giovanni XXIII” Bari Italy
| | - Maria Barile
- Department of Biosciences, Biotechnology and Biopharmaceutics University of Bari “A. Moro” Bari Italy
| |
Collapse
|
5
|
Keegan NP, Wilton SD, Fletcher S. Analysis of Pathogenic Pseudoexons Reveals Novel Mechanisms Driving Cryptic Splicing. Front Genet 2022; 12:806946. [PMID: 35140743 PMCID: PMC8819188 DOI: 10.3389/fgene.2021.806946] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 12/09/2021] [Indexed: 12/16/2022] Open
Abstract
Understanding pre-mRNA splicing is crucial to accurately diagnosing and treating genetic diseases. However, mutations that alter splicing can exert highly diverse effects. Of all the known types of splicing mutations, perhaps the rarest and most difficult to predict are those that activate pseudoexons, sometimes also called cryptic exons. Unlike other splicing mutations that either destroy or redirect existing splice events, pseudoexon mutations appear to create entirely new exons within introns. Since exon definition in vertebrates requires coordinated arrangements of numerous RNA motifs, one might expect that pseudoexons would only arise when rearrangements of intronic DNA create novel exons by chance. Surprisingly, although such mutations do occur, a far more common cause of pseudoexons is deep-intronic single nucleotide variants, raising the question of why these latent exon-like tracts near the mutation sites have not already been purged from the genome by the evolutionary advantage of more efficient splicing. Possible answers may lie in deep intronic splicing processes such as recursive splicing or poison exon splicing. Because these processes utilize intronic motifs that benignly engage with the spliceosome, the regions involved may be more susceptible to exonization than other intronic regions would be. We speculated that a comprehensive study of reported pseudoexons might detect alignments with known deep intronic splice sites and could also permit the characterisation of novel pseudoexon categories. In this report, we present and analyse a catalogue of over 400 published pseudoexon splice events. In addition to confirming prior observations of the most common pseudoexon mutation types, the size of this catalogue also enabled us to suggest new categories for some of the rarer types of pseudoexon mutation. By comparing our catalogue against published datasets of non-canonical splice events, we also found that 15.7% of pseudoexons exhibit some splicing activity at one or both of their splice sites in non-mutant cells. Importantly, this included seven examples of experimentally confirmed recursive splice sites, confirming for the first time a long-suspected link between these two splicing phenomena. These findings have the potential to improve the fidelity of genetic diagnostics and reveal new targets for splice-modulating therapies.
Collapse
Affiliation(s)
- Niall P. Keegan
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
- *Correspondence: Niall P. Keegan,
| | - Steve D. Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
| |
Collapse
|