Metabolic Liver Failure Panel

Summary
Is a 16 gene panel that includes assessment of non-coding variants.

Is ideal for patients with a clinical suspicion of liver-based inborn error of metabolism. The genes on this panel are included in the Comprehensive Metabolism Panel.

Analysis methods
  • PLUS
Availability
4 weeks
Number of genes
16
Test code
ME2501
Panel tier
Tier 1
CPT Code *
81404, 81405, 81406 X4, 81479
* The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

Summary

The Blueprint Genetics Metabolic Liver Failure Panel (test code ME2501):

Read about our accreditations, certifications and CE-marked IVD medical devices here.

ICD Codes

Refer to the most current version of ICD-10-CM manual for a complete list of ICD-10 codes.

Sample Requirements

  • Blood (min. 1ml) in an EDTA tube
  • Extracted DNA, min. 2 μg in TE buffer or equivalent
  • Saliva (Please see Sample Requirements for accepted saliva kits)

Label the sample tube with your patient’s name, date of birth and the date of sample collection.

We do not accept DNA samples isolated from formalin-fixed paraffin-embedded (FFPE) tissue. In addition, if the patient is affected with a hematological malignancy, DNA extracted from a non-hematological source (e.g. skin fibroblasts) is strongly recommended.

Please note that, in rare cases, mitochondrial genome (mtDNA) variants may not be detectable in blood or saliva in which case DNA extracted from post-mitotic tissue such as skeletal muscle may be a better option.

Read more about our sample requirements here.

It has been estimated that metabolic liver diseases account for 13-43% cases of acute liver failure in infants and young children. Galactosemia, tyrosinemia and mitochondrial disorders in young children and Wilsons disease in older children are commonly implicated. A high index of suspicion for metabolic liver diseases should be kept when there is strong family history of consanguinity, recurrent abortions or sibling deaths; and history of recurrent diarrhea, vomiting, failure to thrive or developmental delay. Simple dietary modifications and/or specific management can be life-saving if instituted promptly. Although individually rare, when considered together, liver-based metabolic diseases represent approximately 10% of pediatric liver transplants and, in some centers, are the second most common indication for liver transplant after biliary atresia. In addition to the above mentioned galactosemia, tyrosinemia and Wilson disease genes, this panel includes several genes for glycogen storage diseases, Niemann-Pick disease, a1-antirypsin deficiency, hereditary fructose intolerance and congenital disorder of glycosylation, type Ib, causing hepatic failure. The panel does not include genes for primary mitochondrial hepatopathies, in which the liver involvement is often part of multiorgan manifestations. If there is suspicion of a liver disease caused by fatty acid oxidation defect or urea cycle defect, there are separate panels for those (Fatty Acid Oxidation Syndrome Panel and Hyperammonemia and Urea Cycle Disorder Panel). In addition, genes for hereditary hemocromatosis are found in Hereditary Hemocromatosis Panel. All these genes from different sub-panels are included in the Comprehensive Metabolism Panel.

Genes in the Metabolic Liver Failure Panel and their clinical significance

To view complete table content, scroll horizontally.

Gene Associated phenotypes Inheritance ClinVar HGMD
ALDOB Fructose intolerance, hereditary AR 41 67
ATP7B Wilson disease AR 219 897
FAH Tyrosinemia AR 53 102
GALE Galactose epimerase deficiency AR 12 26
GALK1 Galactokinase deficiency AR 15 44
GALT Galactosemia AR 238 330
LIPA Wolman disease, Cholesterol ester storage disease AR 27 93
MPI Congenital disorder of glycosylation AR 27 20
NPC1 Niemann-Pick disease AR 164 472
NPC2 Niemann-pick disease AR 21 27
PHKA2 Glycogen storage disease, type IXa1/Glycogen storage disease, type IXa2 (Phosphorylase kinase deficiency) XL 36 114
PHKB Glycogen storage disease AR 9 26
PHKG2 Glycogen storage disease AR 12 33
PYGL Glycogen storage disease AR 21 44
SERPINA1 Alpha-1-antitrypsin deficiency AR 49 80
SMPD1 Niemann-Pick disease AR 110 249

Gene refers to the HGNC approved gene symbol; Inheritance refers to inheritance patterns such as autosomal dominant (AD), autosomal recessive (AR), mitochondrial (mi), X-linked (XL), X-linked dominant (XLD) and X-linked recessive (XLR); ClinVar refers to the number of variants in the gene classified as pathogenic or likely pathogenic in this database (ClinVar); HGMD refers to the number of variants with possible disease association in the gene listed in Human Gene Mutation Database (HGMD). The list of associated, gene specific phenotypes are generated from CGD or Mitomap databases.

Non-coding variants covered by Metabolic Liver Failure Panel

To view complete table content, scroll horizontally.

Gene Genomic location HG19 HGVS RefSeq RS-number
ALDOB Chr9:104183575 c.*516T>A NM_000035.3
ALDOB Chr9:104197990 c.-11+1G>C NM_000035.3 rs181639417
ALDOB Chr9:104198194 NM_000035.3 rs185972191
ATP7B Chr13:52518439 c.3061-12T>A NM_000053.3
ATP7B Chr13:52585551 c.-78A>C NM_000053.3
ATP7B Chr13:52585596 c.-123C>A NM_000053.3
ATP7B Chr13:52585596 c.-128_-124delAGCCG NM_000053.3
ATP7B Chr13:52585606 c.-133A>C NM_000053.3
ATP7B Chr13:52585683 c.-210A>T NM_000053.3
ATP7B Chr13:52585894 NM_000053.3 rs1484840087
ATP7B Chr13:52585897 NM_000053.3
ATP7B Chr13:52585915 c.-442G>A NM_000053.3
GALK1 Chr17:73761239 c.-22T>C NM_000154.1 rs545362817
GALT Chr9:34646606 c.-96T>G NM_000155.3
GALT Chr9:34647075 c.83-11T>G NM_000155.3
GALT Chr9:34648082 c.508-29delT NM_000155.3 rs111033711
GALT Chr9:34648519 c.687+66T>A NM_000155.3
GALT Chr9:34648904 c.820+13A>G NM_000155.3 rs111033768
GALT Chr9:34649617 c.1059+56C>T NM_000155.3 rs111033821
NPC1 Chr18:21132700 c.1554-1009G>A NM_000271.4
NPC1 Chr18:21137182 c.882-28A>G/T NM_000271.4
NPC1 Chr18:21137182 c.882-28A>T NM_000271.4
NPC1 Chr18:21137182 c.882-28A>G NM_000271.4
PHKG2 Chr16:30762416 c.96-11G>A NM_000294.2 rs751600886
SERPINA1 Chr14:94854894 c.-5+2dupT NM_000295.4
SERPINA1 Chr14:94854896 c.-5+1G>A NM_000295.4 rs775786225
SMPD1 Chr11:6415102 c.1341-21_1341-18delAATG NM_000543.4 rs1312743513

Test Strengths

The strengths of this test include:

  • CAP accredited laboratory
  • CLIA-certified personnel performing clinical testing in a CLIA-certified laboratory
  • Powerful sequencing technologies, advanced target enrichment methods and precision bioinformatics pipelines ensure superior analytical performance
  • Careful construction of clinically effective and scientifically justified gene panels
  • Some of the panels include the whole mitochondrial genome (please see the Panel Content section)
  • Our Nucleus online portal providing transparent and easy access to quality and performance data at the patient level
  • ~2,000 non-coding disease causing variants in our clinical grade NGS assay for panels (please see ‘Non-coding disease causing variants covered by this panel’ in the Panel Content section)
  • Our rigorous variant classification scheme
  • Our systematic clinical interpretation workflow using proprietary software enabling accurate and traceable processing of NGS data
  • Our comprehensive clinical statements

Test Limitations

This test does not detect the following:

  • Complex inversions
  • Gene conversions
  • Balanced translocations
  • Some of the panels include the whole mitochondrial genome but not all (please see the Panel Content section)
  • Repeat expansion disorders unless specifically mentioned
  • Non-coding variants deeper than ±20 base pairs from exon-intron boundary unless otherwise indicated (please see above Panel Content / non-coding variants covered by the panel).

This test may not reliably detect the following:

  • Low level mosaicism in nuclear genes (variant with a minor allele fraction of 14.6% is detected with 90% probability)
  • Stretches of mononucleotide repeats
  • Low level heteroplasmy in mtDNA (>90% are detected at 5% level)
  • Indels larger than 50bp
  • Single exon deletions or duplications
  • Variants within pseudogene regions/duplicated segments
  • Some disease causing variants present in mtDNA are not detectable from blood, thus post-mitotic tissue such as skeletal muscle may be required for establishing molecular diagnosis.

The sensitivity of this test may be reduced if DNA is extracted by a laboratory other than Blueprint Genetics.

For additional information, please refer to the Test performance section.

The genes on the panel have been carefully selected based on scientific literature, mutation databases and our experience.

Our panels are sectioned from our high-quality, clinical grade NGS assay. Please see our sequencing and detection performance table for details regarding our ability to detect different types of alterations (Table).

Assays have been validated for various sample types including EDTA-blood, isolated DNA (excluding from formalin fixed paraffin embedded tissue), saliva and dry blood spots (filter cards). These sample types were selected in order to maximize the likelihood for high-quality DNA yield. The diagnostic yield varies depending on the assay used, referring healthcare professional, hospital and country. Plus analysis increases the likelihood of finding a genetic diagnosis for your patient, as large deletions and duplications cannot be detected using sequence analysis alone. Blueprint Genetics’ Plus Analysis is a combination of both sequencing and deletion/duplication (copy number variant (CNV)) analysis.

The performance metrics listed below are from an initial validation performed at our main laboratory in Finland. The performance metrics of our laboratory in Marlborough, MA, are equivalent.

Performance of Blueprint Genetics high-quality, clinical grade NGS sequencing assay for panels.

Sensitivity % (TP/(TP+FN) Specificity %
Single nucleotide variants 99.89% (99,153/99,266) >99.9999%
Insertions, deletions and indels by sequence analysis
1-10 bps 99.2% (7,745/7,806) >99.9999%
11-50 bps 99.13% (2,524/2,546) >99.9999%
Copy number variants (exon level dels/dups)
1 exon level deletion (heterozygous) 100% (20/20) NA
1 exon level deletion (homozygous) 100% (5/5) NA
1 exon level deletion (het or homo) 100% (25/25) NA
2-7 exon level deletion (het or homo) 100% (44/44) NA
1-9 exon level duplication (het or homo) 75% (6/8) NA
Simulated CNV detection
5 exons level deletion/duplication 98.7% 100.00%
Microdeletion/-duplication sdrs (large CNVs, n=37))
Size range (0.1-47 Mb) 100% (25/25)
     
The performance presented above reached by Blueprint Genetics high-quality, clinical grade NGS sequencing assay with the following coverage metrics
     
Mean sequencing depth 143X
Nucleotides with >20x sequencing coverage (%) 99.86%

Performance of Blueprint Genetics Mitochondrial Sequencing Assay.

Sensitivity % Specificity %
ANALYTIC VALIDATION (NA samples; n=4)
Single nucleotide variants
Heteroplasmic (45-100%) 100.0% (50/50) 100.0%
Heteroplasmic (35-45%) 100.0% (87/87) 100.0%
Heteroplasmic (25-35%) 100.0% (73/73) 100.0%
Heteroplasmic (15-25%) 100.0% (77/77) 100.0%
Heteroplasmic (10-15%) 100.0% (74/74) 100.0%
Heteroplasmic (5-10%) 100.0% (3/3) 100.0%
Heteroplasmic (<5%) 50.0% (2/4) 100.0%
CLINICAL VALIDATION (n=76 samples)
All types
Single nucleotide variants n=2026 SNVs
Heteroplasmic (45-100%) 100.0% (1940/1940) 100.0%
Heteroplasmic (35-45%) 100.0% (4/4) 100.0%
Heteroplasmic (25-35%) 100.0% (3/3) 100.0%
Heteroplasmic (15-25%) 100.0% (3/3) 100.0%
Heteroplasmic (10-15%) 100.0% (9/9) 100.0%
Heteroplasmic (5-10%) 92.3% (12/13) 99.98%
Heteroplasmic (<5%) 88.9% (48/54) 99.93%
Insertions and deletions by sequence analysis n=40 indels
Heteroplasmic (45-100%) 1-10bp 100.0% (32/32) 100.0%
Heteroplasmic (5-45%) 1-10bp 100.0% (3/3) 100.0%
Heteroplasmic (<5%) 1-10bp 100.0% (5/5) 99,997%
SIMULATION DATA /(mitomap mutations)
Insertions, and deletions 1-24 bps by sequence analysis; n=17
Homoplasmic (100%) 1-24bp 100.0% (17/17) 99.98%
Heteroplasmic (50%) 100.0% (17/17) 99.99%
Heteroplasmic (25%) 100.0% (17/17) 100.0%
Heteroplasmic (20%) 100.0% (17/17) 100.0%
Heteroplasmic (15%) 100.0% (17/17) 100.0%
Heteroplasmic (10%) 94.1% (16/17) 100.0%
Heteroplasmic (5%) 94.1% (16/17) 100.0%
Copy number variants (separate artifical mutations; n=1500)
Homoplasmic (100%) 500 bp, 1kb, 5 kb 100.0% 100.0%
Heteroplasmic (50%) 500 bp, 1kb, 5 kb 100.0% 100.0%
Heteroplasmic (30%) 500 bp, 1kb, 5 kb 100.0% 100.0%
Heteroplasmic (20%) 500 bp, 1kb, 5 kb 99.7% 100.0%
Heteroplasmic (10%) 500 bp, 1kb, 5 kb 99.0% 100.0%
The performance presented above reached by following coverage metrics at assay level (n=66)
Mean of medians Median of medians
Mean sequencing depth MQ0 (clinical) 18224X 17366X
Nucleotides with >1000x MQ0 sequencing coverage (%) (clinical) 100%
rho zero cell line (=no mtDNA), mean sequencing depth 12X

The target region for each gene includes coding exons and ±20 base pairs from the exon-intron boundary. In addition, the panel includes non-coding and regulatory variants if listed above (Non-coding variants covered by the panel). Some regions of the gene(s) may be removed from the panel if specifically mentioned in the ‘Test limitations” section above. If the test includes the mitochondrial genome the target region gene list contains the mitochondrial genes. The sequencing data generated in our laboratory is analyzed with our proprietary data analysis and annotation pipeline, integrating state-of-the art algorithms and industry-standard software solutions. Incorporation of rigorous quality control steps throughout the workflow of the pipeline ensures the consistency, validity and accuracy of results. Our pipeline is streamlined to maximize sensitivity without sacrificing specificity. We have incorporated a number of reference population databases and mutation databases including, but not limited, to 1000 Genomes Project, gnomAD, ClinVar and HGMD into our clinical interpretation software to make the process effective and efficient. For missense variants, in silico variant prediction tools such as  SIFT, PolyPhen,MutationTaster are used to assist with variant classification. Through our online ordering and statement reporting system, Nucleus, ordering providers have access to the details of the analysis, including patient specific sequencing metrics, a gene level coverage plot and a list of regions with suboptimal coverage (<20X for nuclear genes and <1000X for mtDNA) if applicable. This reflects our mission to build fully transparent diagnostics where ordering providers can easily visualize the crucial details of the analysis process.

We provide customers with the most comprehensive clinical report available on the market. Clinical interpretation requires a fundamental understanding of clinical genetics and genetic principles. At Blueprint Genetics, our PhD molecular geneticists, medical geneticists, and clinical consultants prepare the clinical statement together by evaluating the identified variants in the context of the phenotypic information provided in the requisition form. Our goal is to provide clinically meaningful statements that are understandable for all medical professionals regardless of whether they have formal training in genetics.

Variant classification is the cornerstone of clinical interpretation and resulting patient management decisions. Our classifications follow the ACMG guideline 2015.

The final step in the analysis is orthogonal confirmation. Sequence and copy number variants classified as pathogenic, likely pathogenic, and variants of uncertain significance (VUS) are confirmed using bi-directional Sanger sequencing or by orthogonal methods such as qPCR/ddPCR when they do not meet our stringent NGS quality metrics for a true positive call.

Our clinical statement includes tables for sequencing and copy number variants that include basic variant information (genomic coordinates, HGVS nomenclature, zygosity, allele frequencies, in silico predictions, OMIM phenotypes, and classification of the variant). In addition, the statement includes detailed descriptions of the variant, gene, and phenotype(s) including the role of the specific gene in human disease, the mutation profile, information about the gene’s variation in population cohorts, and detailed information about related phenotypes. We also provide links to the references, abstracts, and variant databases used to help ordering providers further evaluate the reported findings if desired. The conclusion summarizes all of the existing information and provides our rationale for the classification of the variant.

Identification of pathogenic or likely pathogenic variants in dominant disorders or their combinations in different alleles in recessive disorders are considered molecular confirmation of the clinical diagnosis. In these cases, family member testing can be used for risk stratification. We do not recommend using variants of uncertain significance (VUS) for family member risk stratification or patient management. Genetic counseling is recommended.

Our interpretation team analyzes millions of variants from thousands of individuals with rare diseases. Our internal database and our understanding of variants and related phenotypes increases with every case analyzed. Our laboratory is therefore well-positioned to re-classify previously reported variants as new information becomes available. If a variant previously reported by Blueprint Genetics is re-classified, our laboratory will issue a follow-up statement to the original ordering healthcare provider at no additional cost, according to our latest follow-up reporting policy.