Monoamine oxidase A activity in fibroblasts as a functional confirmation of MAOA variants

Autor: Nicole de Leeuw, Michèl A.A.P. Willemsen, Marcel M. Verbeek, Karlien L.M. Coene, Ron A. Wevers, Tessa M. A. Peters, Irma Lammerts van Bueren, Jon J. Jonsson, Han G. Brunner, Ben P.B.H. Geurtz
Přispěvatelé: MUMC+: DA Klinische Genetica (5), Klinische Genetica, RS: GROW - R4 - Reproductive and Perinatal Medicine
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Research Report
enzyme assay
lcsh:QH426-470
Endocrinology
Diabetes and Metabolism
Aldehyde dehydrogenase
MAO‐A deficiency
medicine.disease_cause
lcsh:Diseases of the endocrine glands. Clinical endocrinology
Biochemistry
Genetics and Molecular Biology (miscellaneous)
High-performance liquid chromatography
Internal Medicine
medicine
Fibroblast
Gene
functional confirmation
Mutation
Neurodevelopmental disorders Donders Center for Medical Neuroscience [Radboudumc 7]
lcsh:RC648-665
biology
Chemistry
variant of uncertain significance
Metabolic Disorders Radboud Institute for Molecular Life Sciences [Radboudumc 6]
Research Reports
Disorders of movement Donders Center for Medical Neuroscience [Radboudumc 3]
medicine.disease
Molecular biology
Enzyme assay
lcsh:Genetics
medicine.anatomical_structure
Inborn error of metabolism
biology.protein
HPLC
Monoamine oxidase A
Zdroj: JIMD reports, 58(1), 114-121. Springer
JIMD Reports, Vol 58, Iss 1, Pp 114-121 (2021)
JIMD Reports
Jimd Reports, 58, 114-21
Jimd Reports, 58, 1, pp. 114-21
ISSN: 2192-8304
Popis: Monoamine oxidase A (MAO‐A) deficiency is a rare inborn error of metabolism with impaired degradation of biogenic amines including 5‐hydroxytryptamine (5‐HT), resulting in borderline intellectual disability and behavioral abnormalities. Genetic variants in MAOA need functional confirmation to enable a definite diagnosis. To this end, we developed an inexpensive, simple and nonradioactive MAO‐A activity assay based on the conversion of 5‐HT into 5‐hydroxyindoleacetic acid (5‐HIAA). Fibroblast cell lysates were incubated with 5‐HT and aldehyde dehydrogenase to allow 5‐HIAA production. 5‐HIAA was quantified using high‐performance liquid chromatography with fluorimetric detection. We optimized reaction mixture components, pH, and substrate concentration and tested linearity and specificity of the assay. We verified the functional validity of the enzyme assay using fibroblasts of controls, female mutation carriers and MAO‐A deficient patients. This included a newly described patient with a novel MAOA variant (c.1336G>A, p.(Glu446Lys)), who represents the fifth MAO‐A deficiency family so far. The optimized enzyme assay showed good linearity and specificity. Application to clinical samples showed a 100% differentiation of affected patients (with negligible MAO‐A enzyme activity) and controls or mutation carriers. In conclusion, the described MAO‐A activity assay is easy to implement and can readily be used to test the pathogenicity of variants in the MAOA gene in a clinical setting. Especially in this era of whole‐exome (and whole‐genome) sequencing, this functional assay fulfills a clinical need for functional confirmation of a suspected diagnosis of MAO‐A deficiency.
Databáze: OpenAIRE
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