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Madhana Priya N, Sidharth Kumar N, Udhaya Kumar S, Mohanraj G, Magesh R, Zayed H, Vasudevan K, C GPD. Exploring the effect of disease causing mutations in metal binding sites of human ARSA in metachromatic leukodystrophy. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2024; 141:203-221. [PMID: 38960474 DOI: 10.1016/bs.apcsb.2023.12.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
The arylsulfatase A (ARSA) gene is observed to be deficient in patients with metachromatic leukodystrophy (MLD), a type of lysosomal storage disease. MLD is a severe neurodegenerative disorder characterized by an autosomal recessive inheritance pattern. This study aimed to map the most deleterious mutations at the metal binding sites of ARSA and the amino acids in proximity to the mutated positions. We utilized an array of computational tools, including PredictSNP, MAPP, PhD-SNP, PolyPhen-1, PolyPhen-2, SIFT, SNAP, and ConSurf, to identify the most detrimental mutations potentially implicated in MLD collected from UniProt, ClinVar, and HGMD. Two mutations, D29N and D30H, as being extremely deleterious based on assessments of pathogenicity, conservation, biophysical characteristics, and stability analysis. The D29 and D30 are located at the metal-interacting regions of ARSA and found to undergo post-translational modification, specifically phosphorylation. Henceforth, the in-depth effect of metal binding upon mutation was examined using molecular dynamics simulations (MDS) before and after phosphorylation. The MDS results exhibited high deviation for the D29N and D30H mutations in comparison to the native, and the same was confirmed by significant residue fluctuation and reduced compactness. These structural alterations suggest that such mutations may influence protein functionality, offering potential avenues for personalized therapeutic and providing a basis for potential mutation-specific treatments for severe MLD patients.
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Affiliation(s)
- N Madhana Priya
- Department of Biotechnology, Sri Ramachandra Institute of Higher Education and Research (DU), Chennai, Tamil Nadu, India
| | - N Sidharth Kumar
- Laboratory of Integrative Genomics, Department of Integrative Biology, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - S Udhaya Kumar
- Laboratory of Integrative Genomics, Department of Integrative Biology, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India; Department of Medicine, Division Endocrinology, Diabetes and Metabolism, Baylor College of Medicine, Houston, TX, United States
| | - G Mohanraj
- Laboratory of Integrative Genomics, Department of Integrative Biology, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - R Magesh
- Department of Biotechnology, Sri Ramachandra Institute of Higher Education and Research (DU), Chennai, Tamil Nadu, India
| | - Hatem Zayed
- Department of Biomedical Sciences, College of Health Sciences, Qatar University, Doha, Qatar
| | - Karthick Vasudevan
- Department of Biotechnology, School of Applied Sciences, REVA University, Bengaluru, Karnataka, India
| | - George Priya Doss C
- Laboratory of Integrative Genomics, Department of Integrative Biology, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India.
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Trinidad M, Hong X, Froelich S, Daiker J, Sacco J, Nguyen HP, Campagna M, Suhr D, Suhr T, LeBowitz JH, Gelb MH, Clark WT. Predicting disease severity in metachromatic leukodystrophy using protein activity and a patient phenotype matrix. Genome Biol 2023; 24:172. [PMID: 37480112 PMCID: PMC10360315 DOI: 10.1186/s13059-023-03001-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 06/29/2023] [Indexed: 07/23/2023] Open
Abstract
BACKGROUND Metachromatic leukodystrophy (MLD) is a lysosomal storage disorder caused by mutations in the arylsulfatase A gene (ARSA) and categorized into three subtypes according to age of onset. The functional effect of most ARSA mutants remains unknown; better understanding of the genotype-phenotype relationship is required to support newborn screening (NBS) and guide treatment. RESULTS We collected a patient data set from the literature that relates disease severity to ARSA genotype in 489 individuals with MLD. Patient-based data were used to develop a phenotype matrix that predicts MLD phenotype given ARSA alleles in a patient's genotype with 76% accuracy. We then employed a high-throughput enzyme activity assay using mass spectrometry to explore the function of ARSA variants from the curated patient data set and the Genome Aggregation Database (gnomAD). We observed evidence that 36% of variants of unknown significance (VUS) in ARSA may be pathogenic. By classifying functional effects for 251 VUS from gnomAD, we reduced the incidence of genotypes of unknown significance (GUS) by over 98.5% in the overall population. CONCLUSIONS These results provide an additional tool for clinicians to anticipate the disease course in MLD patients, identifying individuals at high risk of severe disease to support treatment access. Our results suggest that more than 1 in 3 VUS in ARSA may be pathogenic. We show that combining genetic and biochemical information increases diagnostic yield. Our strategy may apply to other recessive diseases, providing a tool to address the challenge of interpreting VUS within genotype-phenotype relationships and NBS.
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Affiliation(s)
- Marena Trinidad
- Translational Genomics Group, BioMarin Pharmaceutical Inc., Novato, CA, USA
| | - Xinying Hong
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Steven Froelich
- Translational Genomics Group, BioMarin Pharmaceutical Inc., Novato, CA, USA
| | - Jessica Daiker
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | - James Sacco
- Translational Genomics Group, BioMarin Pharmaceutical Inc., Novato, CA, USA
| | - Hong Phuc Nguyen
- Translational Genomics Group, BioMarin Pharmaceutical Inc., Novato, CA, USA
| | - Madelynn Campagna
- Department of Chemistry, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | | | | | | | - Michael H Gelb
- Department of Chemistry, University of Washington, Seattle, WA, USA.
- Department of Biochemistry, University of Washington, Seattle, WA, USA.
| | - Wyatt T Clark
- Translational Genomics Group, BioMarin Pharmaceutical Inc., Novato, CA, USA.
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Amr K, Fateen E, Mansour L, Tosson AM, Zaki MS, Salam GMA, Mohamed AN, El-Bassyouni HT. Clinical, Biochemical, and Molecular Characterization of Metachromatic Leukodystrophy Among Egyptian Pediatric Patients: Expansion of the ARSA Mutational Spectrum. J Mol Neurosci 2020; 71:1112-1130. [PMID: 33185815 DOI: 10.1007/s12031-020-01734-1] [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: 07/27/2020] [Accepted: 10/14/2020] [Indexed: 11/28/2022]
Abstract
Metachromatic leukodystrophy (MLD) is a neurodegenerative disorder characterized by progressive demyelination due to deficiency of the enzyme arylsulfatase A (ARSA) in leukocytes, and consequently leads to impaired degradation and accumulation of cerebroside-3-sulfate (sulfatide). This study aimed to sequence the ARSA gene in a total of 43 patients with metachromatic leukodystrophy descendant from 40 Egyptian families. In addition, four carrier parents from two families with children who had died from MLD came to the clinic for genetic analysis. Prenatal diagnosis was performed for four families with molecularly diagnosed MLD sibs. Different mutations were characterized in our cohort, including missense, nonsense, splice, and deletion. Overall, 21 different mutations in the ARSA gene were detected, with 12 novel mutations, i.e. p.Arg60Pro, p.Tyr65*, p.Val112Asp, p.Arg116*, p.Gly124Asp, p.Pro193Ser, p.Gln238*, p.Gln456*, p.Thr276Lys, and p.Gly311Arg, in addition to two new acceptor splice-site mutations 685-1G > A and c.954_956 delCTT. The amniotic fluid samples revealed two carrier fetuses with heterozygous monoallelic mutations, and two affected fetuses had the homozygous biallelic mutations. In conclusion, the current study sheds light on the underlying ARSA gene defect, with an expansion of the mutation spectrum. To our knowledge, this is the first molecular study of MLD among the Egyptian population.
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Affiliation(s)
- Khalda Amr
- Medical Molecular Genetics, National Research Center, Cairo, Egypt
| | - Ekram Fateen
- Biochemical Genetics Department, National Research Centre, Cairo, 12622, Postal Code, Egypt
| | - Lobna Mansour
- Pediatrics Department, Faculty of Medicine, Kasr Al Ainy, Cairo University, Cairo, Egypt
| | - Angie Ms Tosson
- Pediatrics Department, Faculty of Medicine, Kasr Al Ainy, Cairo University, Cairo, Egypt
| | - Maha S Zaki
- Clinical Genetics Department, National Research Centre, Cairo, Egypt
| | | | - Ahmed Nabil Mohamed
- Prenatal Diagnosis and Fetal Medicine Department, National Research Centre, Cairo, Egypt
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Beerepoot S, van Dooren SJM, Salomons GS, Boelens JJ, Jacobs EH, van der Knaap MS, van Kuilenburg ABP, Wolf NI. Metachromatic leukodystrophy genotypes in The Netherlands reveal novel pathogenic ARSA variants in non-Caucasian patients. Neurogenetics 2020; 21:289-299. [PMID: 32632536 PMCID: PMC7476914 DOI: 10.1007/s10048-020-00621-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 06/20/2020] [Indexed: 12/21/2022]
Abstract
Metachromatic leukodystrophy (MLD) is an autosomal recessively inherited sulfatide storage disease caused by deficient activity of the lysosomal enzyme arylsulfatase A (ASA). Genetic analysis of the ARSA gene is important in MLD diagnosis and screening of family members. In addition, more information on genotype prevalence will help interpreting MLD population differences between countries. In this study, we identified 31 different ARSA variants in the patient cohort (n = 67) of the Dutch expertise center for MLD. The most frequently found variant, c.1283C > T, p.(Pro428Leu), was present in 43 (64%) patients and resulted in a high prevalence of the juvenile MLD type (58%) in The Netherlands. Furthermore, we observed in five out of six patients with a non-Caucasian ethnic background previously unreported pathogenic ARSA variants. In total, we report ten novel variants including four missense, two nonsense, and two frameshift variants and one in-frame indel, which were all predicted to be disease causing in silico. In addition, one silent variant was found, c.1200C > T, that most likely resulted in erroneous exonic splicing, including partial skipping of exon 7. The c.1200C > T variant was inherited in cis with the pseudodeficiency allele c.1055A > G, p.(Asn352Ser) + ∗96A > G. With this study we provide a genetic base of the unique MLD phenotype distribution in The Netherlands. In addition, our study demonstrated the importance of genetic analysis in MLD diagnosis and the increased likelihood of unreported, pathogenic ARSA variants in patients with non-Caucasian ethnic backgrounds.
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Affiliation(s)
- Shanice Beerepoot
- Amsterdam Leukodystrophy Center, Department of Child Neurology, Emma Children's Hospital, Amsterdam University Medical Center, VU University Amsterdam and Amsterdam Neuroscience, De Boelelaan, 1117, Amsterdam, The Netherlands.,Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Silvy J M van Dooren
- Department of Clinical Chemistry, Metabolic Unit, Amsterdam University Medical Center, VU University Amsterdam, and Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Gajja S Salomons
- Department of Clinical Chemistry, Metabolic Unit, Amsterdam University Medical Center, VU University Amsterdam, and Amsterdam Neuroscience, Amsterdam, The Netherlands.,Department of Clinical Chemistry, Laboratory of Genetic Metabolic Diseases, Amsterdam University Medical Center, University of Amsterdam, Amsterdam Gastroenterology & Metabolism, Amsterdam, The Netherlands
| | - Jaap Jan Boelens
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands.,Department of Pediatrics, Stem Cell Transplant and Cellular Therapies, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Edwin H Jacobs
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Marjo S van der Knaap
- Amsterdam Leukodystrophy Center, Department of Child Neurology, Emma Children's Hospital, Amsterdam University Medical Center, VU University Amsterdam and Amsterdam Neuroscience, De Boelelaan, 1117, Amsterdam, The Netherlands.,Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, The Netherlands
| | - André B P van Kuilenburg
- Department of Clinical Chemistry, Laboratory of Genetic Metabolic Diseases, Amsterdam University Medical Center, University of Amsterdam, Amsterdam Gastroenterology & Metabolism, Amsterdam, The Netherlands
| | - Nicole I Wolf
- Amsterdam Leukodystrophy Center, Department of Child Neurology, Emma Children's Hospital, Amsterdam University Medical Center, VU University Amsterdam and Amsterdam Neuroscience, De Boelelaan, 1117, Amsterdam, The Netherlands. .,Amsterdam UMC, location VUmc, De Boelelaan 1118, 1081 HV, Amsterdam, The Netherlands.
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