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Determination of the frequency of four pathogenic variants causing inborn errors of metabolism in the western cape black population, using a multiplexed arms pcr approach

Background: Carrier frequency determination of repeatedly identified pathogenic variants causing inborn errors of metabolism will enable early diagnosis and treatment of illness, and counselling of prospective parents. Four single nucleotide variants (SNV) were identified in our black South African...

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Main Author: Dalmacio, Ronald
Other Authors: Meldau, Surita
Format: Thesis
Language:English
Published: Department of Pathology 2024
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access_status_str Open Access
author Dalmacio, Ronald
author2 Meldau, Surita
author_browse Dalmacio, Ronald
Meldau, Surita
author_facet Meldau, Surita
Dalmacio, Ronald
author_sort Dalmacio, Ronald
collection Thesis
description Background: Carrier frequency determination of repeatedly identified pathogenic variants causing inborn errors of metabolism will enable early diagnosis and treatment of illness, and counselling of prospective parents. Four single nucleotide variants (SNV) were identified in our black South African population, on two or more separate alleles, namely, c.484C>T(p.Arg162Ter) in the GALNT3 gene causing hyperphosphataemic familial tumoral calcinosis (HFTC); c.803G>A(p.Arg268His) in the OXCT1 gene causing Succinyl-CoA:3-ketoacid CoA transferase (SCOT) deficiency; c.189G>A(p.Trp62Ter) in the G6PC gene causing glycogen storage disease type 1a (GSD 1a), and c.159dupT(p.Asp54*) in the BOLA3 gene causing multiple mitochondrial dysfunction syndrome type 2 (MMDS 2). Analysing large population cohorts for all four variants individually is time-consuming and expensive. Therefore, a simple, cost effective, and robust method like multiplexed ARMS PCR using standard PCR chemistry is attractive for use in resource constrained environments in which common population variants account for most of the disease burden. Methods: ARMS PCR primers were designed to detect the four variants of interest. Individual PCR methods were optimised for each primer pair, followed by an attempt to combine these reactions in a multiplex assay. A multiplex ARMS PCR method designed to detect both the BOLA3 and OXCT1 pathogenic variants listed above was used to screen a cohort of 750 samples, followed by Sanger sequencing to confirm findings in positive cases. Results: Individual PCR reactions performed well for all primer pairs at 54°C annealing temperature. Attempts to combine all four primer sets into a single multiplex reaction repeatedly failed. A smaller multiplex assay containing primers for the BOLA3 and OXCT1 variants showed promise initially, but Sanger sequencing failed to confirm the positive OXCT1 results found in all 14 ARMS PCR positive cases identified. Conclusions: This study investigated the feasibility of using multiplexed ARMS PCR to screen for multiple variants simultaneously in a clinically unaffected cohort. This study highlights the challenges of combining PCR reactions. Troubleshooting is laborious, time-consuming and may delay obtaining frequencies. The carrier frequency of the four IEM causing variants investigated in this study requires individual PCR assays, unless multiplex assays are optimised, or other methods are used.
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institution University of Cape Town (South Africa)
language eng
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license_str Not specified — see source repository
provenance_str_mv Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository
publishDate 2024
publishDateRange 2024
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spelling oai:open.uct.ac.za:11427/39408 Determination of the frequency of four pathogenic variants causing inborn errors of metabolism in the western cape black population, using a multiplexed arms pcr approach Dalmacio, Ronald Meldau, Surita Chemical Pathology Background: Carrier frequency determination of repeatedly identified pathogenic variants causing inborn errors of metabolism will enable early diagnosis and treatment of illness, and counselling of prospective parents. Four single nucleotide variants (SNV) were identified in our black South African population, on two or more separate alleles, namely, c.484C>T(p.Arg162Ter) in the GALNT3 gene causing hyperphosphataemic familial tumoral calcinosis (HFTC); c.803G>A(p.Arg268His) in the OXCT1 gene causing Succinyl-CoA:3-ketoacid CoA transferase (SCOT) deficiency; c.189G>A(p.Trp62Ter) in the G6PC gene causing glycogen storage disease type 1a (GSD 1a), and c.159dupT(p.Asp54*) in the BOLA3 gene causing multiple mitochondrial dysfunction syndrome type 2 (MMDS 2). Analysing large population cohorts for all four variants individually is time-consuming and expensive. Therefore, a simple, cost effective, and robust method like multiplexed ARMS PCR using standard PCR chemistry is attractive for use in resource constrained environments in which common population variants account for most of the disease burden. Methods: ARMS PCR primers were designed to detect the four variants of interest. Individual PCR methods were optimised for each primer pair, followed by an attempt to combine these reactions in a multiplex assay. A multiplex ARMS PCR method designed to detect both the BOLA3 and OXCT1 pathogenic variants listed above was used to screen a cohort of 750 samples, followed by Sanger sequencing to confirm findings in positive cases. Results: Individual PCR reactions performed well for all primer pairs at 54°C annealing temperature. Attempts to combine all four primer sets into a single multiplex reaction repeatedly failed. A smaller multiplex assay containing primers for the BOLA3 and OXCT1 variants showed promise initially, but Sanger sequencing failed to confirm the positive OXCT1 results found in all 14 ARMS PCR positive cases identified. Conclusions: This study investigated the feasibility of using multiplexed ARMS PCR to screen for multiple variants simultaneously in a clinically unaffected cohort. This study highlights the challenges of combining PCR reactions. Troubleshooting is laborious, time-consuming and may delay obtaining frequencies. The carrier frequency of the four IEM causing variants investigated in this study requires individual PCR assays, unless multiplex assays are optimised, or other methods are used. 2024-04-18T12:54:01Z 2024-04-18T12:54:01Z 2023 2024-04-18T12:27:10Z Thesis / Dissertation Masters MMed http://hdl.handle.net/11427/39408 eng application/pdf Department of Pathology Faculty of Health Sciences
spellingShingle Chemical Pathology
Dalmacio, Ronald
Determination of the frequency of four pathogenic variants causing inborn errors of metabolism in the western cape black population, using a multiplexed arms pcr approach
thesis_degree_str Master's
title Determination of the frequency of four pathogenic variants causing inborn errors of metabolism in the western cape black population, using a multiplexed arms pcr approach
title_full Determination of the frequency of four pathogenic variants causing inborn errors of metabolism in the western cape black population, using a multiplexed arms pcr approach
title_fullStr Determination of the frequency of four pathogenic variants causing inborn errors of metabolism in the western cape black population, using a multiplexed arms pcr approach
title_full_unstemmed Determination of the frequency of four pathogenic variants causing inborn errors of metabolism in the western cape black population, using a multiplexed arms pcr approach
title_short Determination of the frequency of four pathogenic variants causing inborn errors of metabolism in the western cape black population, using a multiplexed arms pcr approach
title_sort determination of the frequency of four pathogenic variants causing inborn errors of metabolism in the western cape black population using a multiplexed arms pcr approach
topic Chemical Pathology
url http://hdl.handle.net/11427/39408
work_keys_str_mv AT dalmacioronald determinationofthefrequencyoffourpathogenicvariantscausinginbornerrorsofmetabolisminthewesterncapeblackpopulationusingamultiplexedarmspcrapproach