Abstract
Clinical diagnosis of inborn errors of metabolism in the suspected patients is usually guided by the initial general investigations in the laboratory such as the concentration of ammonia, blood gases status, blood glucose and ketones. The establishment of a biochemical diagnosis in patients with inborn errors of metabolism depends on the detection of the specific metabolites in the abnormal metabolic pathway which can appear in any of the body fluids but are most commonly tested in blood and urine samples. Acylcarnitine and/or acylcarnitine ratio in patients with carnitine acylcarnitine translocase and carnitine palmitoyl transferase deficiency showed an abnormal profile regardless of the metabolic status of patients. The acylcarnitine was derived from the analysis of dried blood spot using multiple reaction monitoring (MRM) which was performed using quadrupole mass spectrometry. The dataset presented in this article was generated from analysis of acylcarnitines in the 17,121 dried blood spots from symptomatic Malaysian patients less than fifty years old who exhibited symptoms suggestive of inborn errors of metabolism, but had a normal acylcarnitine profile. A precursor or ion scan of m/z 85 was selected for the analysis. Quantification of each analyte was obtained using the signal intensity ratio of the acylcarnitine to its internal standard. The acylcarnitines analyzed included C0, C2, C3, C3DC, C4, C5, C5:1, C5DC, C5OH, C6, C8, C10, C12, C14, C16, C18, C18:1, C16OH, C18OH and C18:1OH and was analyzed using Neolynx V4.0 software. We decided to choose the 1st and 99th percentiles as the minimum and maximum cut-offs. The filtered part of data in this article was used in the article Novel mutations associated with Carnitine-Acylcarnitine Translocase and Carnitine Palmitoyl Transferase 2 deficiencies in Malaysia. This dataset is intended to enable the scientific communities to get access to the raw dataset for future translational research use in inborn errors of metabolism as very few acylcarnitine data was developed and published for the symptomatic patients suspected of inborn errors of metabolism especially in the Asian population.
Keywords: Inborn errors of metabolism, tandem mass spectrometry, Carnitine-acylcarnitine translocase deficiency, Carnitine palmitoyl transferase 2 deficiency, Acylcarnitine
Specifications Table
| Subject | Clinical Biochemistry |
| Specific subject area | Inborn errors of metabolism. Inborn errors of metabolism (IEM) are rare genetic diseases which are caused by either deficiency in the enzyme or transport protein in the metabolic pathway. |
| Type of data | Table, figure, excel file, chromatogram MRM, ion spectrum |
| How the data were acquired | Waters Alliance 2975 HPLC system were used for injection of samples. Acylcarnitines and amino acids were analyzed with tandem mass spectrometry using a Micromass Quattro (Waters Corp., Wilmslow, UK) operated with electrospray in positive ion mode. The data was analyzed using Neolynx V4.0 software |
| Data format | Raw data, Analyzed |
| Description of data collection | The data was derived from analysis of acylcarnitines of symptomatic Malaysian patients less than fifty years who exhibiting symptoms suggestive of inborn errors of metabolism but laboratory investigations were not supportive of disease. Data set were filtered to exclude outlier data. The 1st and 99th percentiles were set as the minimum and maximum cut-offs. |
| Data source location | Institution: National Institutes of Health, Institute for Medical Research City/Town/Region: Kuala Lumpur, Wilayah Persekutuan Country: Malaysia Latitude and longitude for collected samples/data: Latitude: 3.169904. Longitude: 101.699173. The raw data was diagnostic data that was taken from diagnostic repository |
| Data accessibility | Repository name: Mendeley data Data identification number: https://data.mendeley.com/datasets/zzgfhbvzg4/2 |
| Related research article | Anasufiza Habib, Nor Azimah Binti Abdul Azize, Salina Binti Abdul Rahman, Yusnita Yakob, Vengadeshwaran A/l Suberamaniam, Muhd Irfan Bukhari Ahmad Nazri, Huzaimah Abdullah Sani, Ch'ng Gaik-siew, Leong Huey Yin, Simon Olpin, Ngu Lock-Hock. Novel Mutations Associated with Carnitine-Acylcarnitine Translocase and Carnitine Palmitoyl Transferase 2 Deficiencies in Malaysia. https://doi.org/10.1016/j.clinbiochem.2021.10.002 |
Value of the Data
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These data on the acylcarnitines derived from the dried blood spot (DBS) and their respective calculated acylcarnitine ratios can be applied in patients with clinically suspected inborn errors of metabolism, the long chain fatty acid oxidation disorders, Carnitine-acylcarnitine Translocase (CACT) deficiency and carnitine palmitoyl transferase 2 (CPT2) deficiency
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These data will benefit the laboratorian and clinician working in the biochemical genetic field and clinical genetics who uses dried blood spot acylcarnitine to screen symptomatic patients for inborn errors of metabolism
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These data can also be used as a reference for the development of reference ranges especially in the Asian patients’ population.
1. Objective
Clinical diagnosis of inborn errors of metabolism in the suspected patients is usually guided by the initial general investigations in the laboratory such as the concentration of ammonia, blood gases status, blood glucose and ketones. The establishment of a biochemical diagnosis in patients with inborn errors of metabolism, depends on detection of the specific metabolites in the abnormal metabolic pathway which can appear in any of the body fluids but are most tested in blood and urine samples. Depending on the metabolic status of the patients, it is not uncommon to find a normal finding in the patients affected with inborn errors of metabolism. In contrast, acylcarnitine and/or acylcarnitine ratio in patients with carnitine acylcarnitine translocase and carnitine palmitoyl transferase deficiency showed an abnormal profile regardless of the metabolic status. This dataset is intended to enable the scientific communities to get access to the raw dataset for future translational research use in inborn errors of metabolism as very few acylcarnitine data were developed and published for the symptomatic patients suspected of inborn errors of metabolism, especially in the Asian population.
2. Data Description
Raw data that can be accessed at Mendeley data (https://data.mendeley.com/datasets/zzgfhbvzg4/2) include the Multiple reaction monitoring (MRM) data and ion spectrums from five patients and normal control. MRM is a highly specific and sensitive label-free technique for quantifying targeted compounds such as proteins. The acylcarnitine was derived from the analysis of dried blood spot using this technique which was performed using quadrupole mass spectrometry. The triple quadrupole mass spectrometry has the ability to select a pre-defined parent or precursor peptide ion of the target protein (MS1) based on charge-to-mass ratio (m/z), subject them to a collision in the vacuum, collision-induced dissociation (CID) and cause fragmentation of ions, and then monitoring and selection of fragments of product ions (MS2), based on the selected predefined m/z will be done by the third quadrupole. The raw MRM chromatogram and the ion spectrum data that was shared in the Mendeley data illustrate the MRM chromatogram and the ion spectrums of individual patients 2 to 6 as described in the previously published paper [1]. Table 1 showed the composition of the standard mixture of labeled acylcarnitine, purchased from Cambridge Isotope Laboratories that was used in the experiments for the semi-quantitation of the analyzed acylcarnitine. Table 2 showed the individual mass of butyl-ester acylcarnitine which can be visualized on the individual ion spectrums chromatogram in the raw dataset. Our dataset in Table 3 was derived from the raw dataset of high risk acylcarnitine excel file in the Mendeley data. The dataset in Table 3 was produced by using simple statistical method for a non-normal distributed data which is commonly found in rare genetic diseases. The individual acylcarnitine mean, median, 1st and 99th percentile was determined (Table 1). The cut-off values for acylcarnitine were determined using 17,121 samples. The acylcarnitine ratios that were calculated were as described by Chace et al. [3]. We use the 99th percentile as the cut-off value for all the analytes except for C0 as in the previous healthy newborn screening study [2]. The standard unit for the individual acylcarnitine is μmol/L. This dataset helps to identify patients suspected of Carnitine-acylcarnitine Translocase (CACT) deficiency and Carnitine Palmitoyl Transferase 2 (CPT2) deficiency as found in the published article [1]. The raw research data is available at https://data.mendeley.com/datasets/zzgfhbvzg4/2
Table 1.
Composition of standard mixture of labeled acylcarnitines from Cambridge Isotope Laboratories.
| Component Isotope Label | Concentration (µM) |
|---|---|
| L-Carnitine (trimethyl-D9, 98% | 150.5 |
| O-Acetyl-L-carnitine:HCL (N-methyl-D3, 98%) | 36.8 |
| O-Propionyl-L-carnitine:HCL (N-methyl-D3, 98%) | 7.5 |
| O-Butyrl-L-carnitine:HCL, (N-methyl-D3, 98%) | 7.4 |
| O-Isovaleryl-L-carnitine:HCL (N,N,N-trimethyl-D9, 98%) | 7.5 |
| O-Octanoyl-L-carnitine:HCL (N-methyl-D3, 98%) | 7.6 |
| O-Myristoyl-L-carnitine:HCL (N, N, N-trimethyl-D9, 98%) | 7.5 |
| O-Palmitoyl-L-carnitine:HCL (N-methyl-D3, 98%) | 15 |
Table 2.
Mass of butyl-ester acylcarnitines.
| Analyte | Mass of butyl ester [M+H]+ |
|---|---|
| Carnitine, C0 | 218 |
| Acetylcarnitine, C2 | 260 |
| Propionylcarnitine, C3 | 273 |
| Butrylcarnitine, C4 | 288 |
| Tiglyl carnitine, C5:1 | 300 |
| Isovaleryl carnitine, C5 | 302 |
| 3-Hydroxy-butyryl carnitine, C4-OH | 304 |
| Hexanoyl carnitine, C6 | 315 |
| 3-Hydroxy-isovaleryl carnitine, C5-OH | 318 |
| Octanoyl carnitine, C8 | 344 |
| Malonyl carnitine, C3DC | 360 |
| Decenoyl carnitine, C10:1 | 369 |
| Decanoyl carnitine, C10 | 371 |
| Glutaryl carnitine, C5DC | 388 |
| Dodecanoyl carnitine, C12:1 | 397 |
| Dodecanoyl carnitine, C12 | 400 |
| Adipoyl carnitine, C6DC | 401 |
| Tetradecadienoyl carnitine, C14:2 | 424 |
| Tetradecenoyl carnitine, C14:1 | 426 |
| Myristoyl carnitine, C14 | 428 |
| Subaryl carnitine, C8DC | 430 |
| 3-hydroxy myristoyl carnitine, C14OH | 444 |
| Palmitoleyl carnitine, C16:1 | 454 |
| Palmitoyl carnitine, C16 | 456 |
| 3-hydroxy palmitoleyl carnitine, C16:1OH | 470 |
| 3-hydroxy palmitoyl carnitine, C16OH | 472 |
| Linoleyl carnitine, C18:2 | 480 |
| Oleyl carnitine, C18:1 | 482 |
| Stearoyl carnitine, C18 | 483 |
| 3-hydroxy linoleyl carnitine, C18:2OH | 496 |
| 3-hydroxy olely carnitine, C18:1OH | 497 |
Table 3.
Acylcarnitines and acylcarnitine ratios for selective high-risk screening for inborn errors of metabolism.
| Acylcarnitines/ratio | Mean | Median | 1st Percentile | 99th percentile | Unit |
|---|---|---|---|---|---|
| C0 | 31.4 | 28.6 | 8 | 85 | µmol/L |
| C2 | 16.83 | 14.63 | 3 | 53 | µmol/L |
| C3 | 1.44 | 1.21 | 0.2 | 5 | µmol/L |
| C4 | 0.3 | 0.25 | 0.07 | 1.11 | µmol/L |
| C5:1 | 0.07 | 0.06 | 0.01 | 0.2 | µmol/L |
| C5 | 0.16 | 0.14 | 0.04 | 0.48 | µmol/L |
| C4OH | 0.15 | 0.12 | 0.02 | 0.64 | µmol/L |
| C6 | 0.11 | 0.09 | 0.01 | 0.46 | µmol/L |
| C5OH | 0.17 | 0.16 | 0.04 | 0.47 | µmol/L |
| C8 | 0.13 | 0.11 | 0.02 | 0.4 | µmol/L |
| C3DC | 0.08 | 0.07 | 0.01 | 0.23 | µmol/L |
| C10:1 | 0.11 | 0.1 | 0.01 | 0.34 | µmol/L |
| C10 | 0.15 | 0.12 | 0.02 | 0.64 | µmol/L |
| C5DC | 0.06 | 0.06 | 0.01 | 0.2 | µmol/L |
| C12:1 | 0.13 | 0.11 | 0.02 | 0.4 | µmol/L |
| C12 | 0.14 | 0.12 | 0.02 | 0.47 | µmol/L |
| C6DC | 0.15 | 0.13 | 0 | 0.46 | µmol/L |
| C14:2 | 0.07 | 0.06 | 0.01 | 0.24 | µmol/L |
| C14:1 | 0.13 | 0.11 | 0.02 | 0.46 | µmol/L |
| C14 | 0.23 | 0.2 | 0.04 | 0.73 | µmol/L |
| C8DC | 0.07 | 0.06 | 0.01 | 0.27 | µmol/L |
| C14OH | 0.05 | 0.05 | 0.01 | 0.2 | µmol/L |
| C16:1 | 0.15 | 0.12 | 0.02 | 0.53 | µmol/L |
| C16 | 1.58 | 1.32 | 0.3 | 5.4 | µmol/L |
| C16:1OH | 0.08 | 0.06 | 0.01 | 0.31 | µmol/L |
| C16OH | 0.05 | 0.04 | 0.01 | 0.19 | µmol/L |
| C18:2 | 0.31 | 0.28 | 0.05 | 0.92 | µmol/L |
| C18:1 | 1.01 | 0.93 | 0.21 | 2.68 | µmol/L |
| C18 | 0.56 | 0.51 | 0.12 | 1.53 | µmol/L |
| C18:2OH | 0.04 | 0.03 | 0 | 0.16 | µmol/L |
| C18:1OH | 0.04 | 0.04 | 0 | 0.17 | µmol/L |
| C16OH/C16 | 0.04 | 0.03 | 0.002 | 0.22 | NA |
| [C16+C18:1]/C2 | 0.18 | 0.16 | 0.04 | 0.58 | NA |
| C14:1/C4 | 0.54 | 0.42 | 0.07 | 2.33 | NA |
| C14:1/C16 | 0.1 | 0.08 | 0.01 | 0.45 | NA |
| C14:1/C12:1 | 1.33 | 0.96 | 0.16 | 7 | NA |
| C0/[C16+C18] | 17.55 | 14.59 | 4 | 53 | NA |
NA, not applicable
3. Experimental Design, Materials and Methods
Malaysia has embarked on a diagnostic service for selective high-risk screening for common inborn errors of metabolism after the completion of the pilot study of newborn screening for inborn errors of metabolism in 2008 [2]. We received on average 7,000 samples of dried blood samples per year. A separate reference range for patients above seven days old was produced from the samples that were sent as part of the investigations to exclude the inborn errors of metabolism. This is due to that acylcarnitine showed a remarkable fall in concentration, especially after seven days of life. The reference ranges were reviewed frequently taking into account the yearly external quality performance, from the Centre for disease control (CDC), Atlanta enrolled by the laboratory. The dataset presented in this article was generated from analysis of acylcarnitine in the 17,121 dried blood spots from symptomatic Malaysian patients less than fifty years old who exhibiting symptoms suggestive of inborn errors of metabolism, but had normal acylcarnitine profile.
3.1. Derivatisation of acylcarnitine in dried blood spot
3.2 mm spots from the dried blood spot samples were punched out into a 96 well plate. A 200 µL of solution containing internal standard was then added into each 96 well plate and mixed. The supernatant was then transferred into a new 96 well plate and dried under nitrogen at 60⁰C for 30 min. Subsequently, 80 µL butanolic acid was added and the samples were incubated at 60⁰C for 30 min. After the butylation, the samples were dried under nitrogen at 60⁰C for 30 min. The residue was redissolved with 150 µL of acetonitrile/water (80:20) prior to analysis as shown in Fig. 1.
Fig. 1.
Schematic overview of the procedure for analysis amino acids and acylcarnitines of dried blood spot.
3.2. Tandem mass spectrometry parameters
A Quattro Micromass system operated with electrospray positive ion mode coupled with Waters Alliance 2975 HPLC that was optimized for acylcarnitine analysis. Source temperature and desolvation temperature were set at 150⁰C and 600⁰C. Scan mode Parents 85 was selected throughout the analysis. For all analytes, acylcarnitine were quantified by calculating ion abundance ratios of pure unlabeled compound relative to their respective stable isotope-labeled internal standards.
Ethics Statements
The original research was approved by the Medical Research and Ethics Committee (MREC) (approval ID: NMRR-21-612-58280) and it was performed according to the Declaration of Helsinki.
CRediT authorship contribution statement
Anasufiza Habib: Conceptualization, Methodology, Data curation, Writing – original draft, Writing – review & editing. Muhammad Irfan Bukhari Ahmad Nazri: Visualization, Investigation, Software, Validation. Salina Abdul Rahman: Methodology, Software, Validation, Writing – review & editing.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgment
We would like to thank the Director General of Health Malaysia for permission to publish this paper. We also thank the staffs of Biochemistry Unit, Institute for Medical Research for their assistance in the laboratory work.
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Data Availability
References
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