Metabolic Epilepsy Panel

Updated
Summary
  • Is a 84 gene panel that includes assessment of non-coding variants.
  • In addition, it also includes the maternally inherited mitochondrial genome. Is ideal for patients with a clinical suspicion of an inherited metabolic disorder causing epileptic seizures. The genes on this panel are included on the Comprehensive Epilepsy Panel.

Analysis methods
  • PLUS
Availability

4 weeks

Number of genes

84

Test code

NE1601

Panel size

Large

CPT code *
81443(1)
* 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 Epilepsy Panel (test code NE1601):

ICD codes

Commonly used ICD-10 code(s) when ordering the Metabolic Epilepsy Panel

ICD-10 Disease
F84.2 Rett syndrome
E72.21 Argininemia
E77.1 Aspartylglucosaminuria
D81.810 Biotinidase deficiency
E88.89 Dihydropyrimidine dehydrogenase deficiency
C74.1 C75.5 D35.0 Hereditary pheochromocytoma-paraganglioma
E72.4 Hyperornithinemia-hyperammonemia-homocitrullinuria
E72.19 Isolated sulfite oxidase deficiency
H49.40 Progressive external ophthalmoplegia
G11.9 Hereditary ataxia
C94.2 Acute Megakaryoblastic Leukemia
K59.8 Chronic Intestinal Pseudoobstruction
T36.5 Adverse effect of aminoglycosides
G93.41 Metabolic Encephalopathy
H49.81 Kearns Sayre Syndrome
E88.42 MERFF Syndrome
H47.013 Nonarteritic Anterior Ischemic Optic Neuropathy
G60.2 Neuropathy in association with hereditary ataxia
G30 Alzheimer's Disease
G25.5 Chorea
G40 Epilepsy and recurrent seizures
I42 Cardiomyopathy
N26.9 Focal Segmental Glomerulosclerosis
G31.82 Leigh's Disease
H47.2 Leber's hereditary optic neuropathy
G71.3 Mitochondrial Myopathy
I42.1 Hypertrophic Cardiomyopathy
E11.9 Non-Insulin Dependent Diabetes Mellitus
Z86.74 Personal history of sudden cardiac arrest
H90.3 Sensorineural Hearing Loss

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.

Epileptic seizures are a frequent symptom in metabolic disease, having been reported in more than 200 different inborn errors of metabolism (IEMs), and seizures are a relatively common reason for referral to the metabolic paediatrician or biochemical geneticist (PubMed: 22998469). The mainstay for the diagnosis of inborn errors of metabolism (IEMs) is biochemical investigation as metabolites may be assayed in blood, urine, or CSF. Genetic diagnosis constitutes the first line of investigation in those instances where there are no characteristic metabolites or diagnostic enzyme assay available or when the metabolite results are unclear. In several instances, genetic testing confirms the diagnosis suggested by biochemical analysis. Genetic testing is leading to the expansion of the epileptic phenotypes of many of the genetic and metabolic epilepsies. It is important to recognize and diagnose this group of disorders, since they may be treatable, and there are significant implications for genetic counselling.

Genes in the Metabolic Epilepsy Panel and their clinical significance

Gene Associated phenotypes Inheritance ClinVar HGMD
ABAT GABA-transaminase deficiency AR 11 12
ADSL Adenylosuccinase deficiency AR 24 57
AGA Aspartylglucosaminuria AR 48 37
ALDH5A1 Succinic semialdehyde dehydrogenase deficiency AR 16 70
ALDH7A1 Epilepsy, pyridoxine-dependent AR 52 123
AMT Glycine encephalopathy AR 42 95
ARG1 Hyperargininemia AR 28 54
BTD Biotinidase deficiency AR 170 247
D2HGDH D-2-hydroxyglutaric aciduria 1 AR 13 33
DHFR* Megaloblastic anemia due to dihydrofolate reductase deficiency AR 2 5
DNM1L Encephalopathy due to defective mitochondrial and peroxisomal fission 1 AD 17 20
DPYD 5-fluorouracil toxicity, Developmental delay with or without dysmorphic facies and autism AD/AR 62 86
DPYS Dihydropyriminidase deficiency AR 8 29
ETFA Glutaric aciduria, Multiple acyl-CoA dehydrogenase deficiency AR 8 29
ETFB Glutaric aciduria, Multiple acyl-CoA dehydrogenase deficiency AR 6 15
ETFDH Glutaric aciduria, Multiple acyl-CoA dehydrogenase deficiency AR 43 190
ETHE1 Ethylmalonic encephalopathy AR 38 36
FH Hereditary leiomyomatosis and renal cell cancer AD/AR 178 207
GAMT Guanidinoacetate methyltransferase deficiency AR 18 58
GCDH Glutaric aciduria AR 90 241
GCH1 Dopa-Responsive Dystonia Hyperphenylalaninemia, BH4-deficient, GTP Cyclohydrolase 1-Deficient Dopa-Responsive Dystonia AD/AR 48 240
GLDC Glycine encephalopathy AR 139 425
GNE Proximal myopathy and ophthalmoplegia, Nonaka myopathy, Sialuria AD/AR 78 214
GPHN Hyperekplexia, Molybdenum cofactor deficiency AD/AR 35 20
HIBCH 3-hydroxyisobutryl-CoA hydrolase deficiency AR 18 16
L2HGDH L-2-hydroxyglutaric aciduria AR 15 79
MIPEP* Combined oxidative phosphorylation deficiency 31 AR 5 8
MOCS1* Molybdenum cofactor deficiency AR 7 35
MT-ATP6 Neuropathy, ataxia, and retinitis pigmentosa, Leber hereditary optic neuropathy, Ataxia and polyneuropathy, adult-onset, Cardiomyopathy, infantile hypertrophic, Leigh syndrome, Striatonigral degeneration, infantile, mitochondrial Mitochondrial 19
MT-ATP8 Cardiomyopathy, apical hypertrophic, and neuropathy, Cardiomyopathy, infantile hypertrophic Mitochondrial 4
MT-CO1 Myoglobinuria, recurrent, Leber hereditary optic neuropathy, Sideroblastic anemia, Cytochrome C oxidase deficiency Mitochondrial 17
MT-CO2 Cytochrome c oxidase deficiency Mitochondrial 8
MT-CO3 Cytochrome c oxidase deficiency, Leber hereditary optic neuropathy Mitochondrial 9
MT-CYB Mitochondrial 69
MT-ND1 Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes, Leber hereditary optic neuropathy, Leber optic atrophy and dystonia Mitochondrial 21
MT-ND2 Leber hereditary optic neuropathy, Mitochondrial complex I deficiency Mitochondrial 6
MT-ND3 Leber optic atrophy and dystonia, Mitochondrial complex I deficiency Mitochondrial 7
MT-ND4 Leber hereditary optic neuropathy, Leber optic atrophy and dystonia, Mitochondrial complex I deficiency Mitochondrial 11
MT-ND4L Leber hereditary optic neuropathy Mitochondrial 2
MT-ND5 Myoclonic epilepsy with ragged red fibers, Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes, Leber hereditary optic neuropathy, Mitochondrial complex I deficiency Mitochondrial 19
MT-ND6 Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes, Oncocytoma, Leber hereditary optic neuropathy, Leber optic atrophy and dystonia, Mitochondrial complex I deficiency Mitochondrial 16
MT-RNR1 Deafness, mitochondrial Mitochondrial 3
MT-RNR2 Chloramphenicol toxicity/resistance Mitochondrial 2
MT-TA Mitochondrial 4
MT-TC Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes Mitochondrial 3
MT-TD Mitochondrial 1
MT-TE Diabetes-deafness syndrome, Mitochondrial myopathy, infantile, transient, Mitochondrial myopathy with diabetes Mitochondrial 5
MT-TF Myoclonic epilepsy with ragged red fibers, Nephropathy, tubulointerstitial, Encephalopathy, mitochondrial, Epilepsy, mitochondrial, Myopathy, mitochondrial, Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes Mitochondrial 7
MT-TG Mitochondrial 3
MT-TH Mitochondrial 4
MT-TI Mitochondrial 7
MT-TK Mitochondrial 5
MT-TL1 Cytochrome c oxidase deficiency, Myoclonic epilepsy with ragged red fibers, Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes, Diabetes-deafness syndrome, Cyclic vomiting syndrome, SIDS, susceptibility to Mitochondrial 14
MT-TL2 Mitochondrial multisystemic disorder, Progressive external ophthalmoplegia Mitochondrial 5
MT-TM Leigh syndrome, Mitochondrial multisystemic disorder Mitochondrial 1
MT-TN Progressive external ophthalmoplegia, Mitochondrial multisystemic disorder Mitochondrial 3
MT-TP Mitochondrial 2
MT-TQ Mitochondrial multisystemic disorder Mitochondrial 2
MT-TR Encephalopathy, mitochondrial Mitochondrial 2
MT-TS1 Myoclonic epilepsy with ragged red fibers, Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes Mitochondrial 10
MT-TS2 Mitochondrial multisystemic disorder Mitochondrial 2
MT-TT Mitochondrial 5
MT-TV Hypertrophic cardiomyopathy (HCM), Leigh syndrome, Mitochondrial multisystemic disorder Mitochondrial 3
MT-TW Leigh syndrome, Myopathy, mitochondrial Mitochondrial 8
MT-TY Mitochondrial multisystemic disorder Mitochondrial 4
MTHFR Homocystinuria due to MTHFR deficiency AR 65 122
NDUFAF3 Mitochondrial complex I deficiency AR 6 9
NDUFS6 Mitochondrial complex I deficiency AR 6 7
PGK1 Phosphoglycerate kinase 1 deficiency XL 16 26
PNPO Pyridoxamine 5'-phosphate oxidase deficiency AR 15 31
POLG POLG-related ataxia neuropathy spectrum disorders, Sensory ataxia, dysarthria, and ophthalmoparesis, Alpers syndrome, Progressive external ophthalmoplegia with mitochondrial DNA deletions, Mitochondrial DNA depletion syndrome AD/AR 89 290
PRODH* Hyperprolinemia AR 52 10
PTS Hyperphenylalaninemia, BH4-deficient AR 34 112
QDPR Hyperphenylalaninemia, BH4-deficient AR 14 66
SERAC1 3-methylglutaconic aciduria with deafness, encephalopathy, and Leigh-like syndrome AR 22 52
SLC25A1 Combined D-2- and L-2-hydroxyglutaric aciduria AR 8 24
SLC25A15* Hyperornithinemia-hyperammonemia-homocitrullinemia syndrome AR 24 36
SLC25A42 AR 1 1
SLC2A1 Stomatin-deficient cryohydrocytosis with neurologic defects, Epilepsy, idiopathic generalized, GLUT1 deficiency syndrome AD/AR 106 275
SLC39A8# Congenital disorder of glycosylation, type IIn AR 7 6
SLC46A1 Folate malabsorption AR 17 23
SUOX Sulfocysteinuria AR 8 29
TPK1 Thiamine metabolism dysfunction syndrome 5 AR 14 11
WARS2 Encephalopathy, mitochondrial AR 6 14

* Some, or all, of the gene is duplicated in the genome. Read more.

# The gene has suboptimal coverage (means <90% of the gene’s target nucleotides are covered at >20x with mapping quality score (MQ>20) reads), and/or the gene has exons listed under Test limitations section that are not included in the panel as they are not sufficiently covered with high quality sequence reads.

The sensitivity to detect variants may be limited in genes marked with an asterisk (*) or number sign (#)

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 Epilepsy Panel

Gene Genomic location HG19 HGVS RefSeq RS-number
ADSL Chr22:40742514 c.-49T>C NM_000026.2
AMT Chr3:49459938 c.-55C>T NM_000481.3 rs386833677
ARG1 Chr6:131901748 c.306-611T>C NM_000045.3
BTD Chr3:15683399 c.310-15delT NM_000060.2 rs587783008
BTD Chr3:15687154 c.*159G>A NM_000060.2 rs530872564
D2HGDH Chr2:242680425 c.293-23A>G NM_152783.3
ETFDH Chr4:159593534 c.-75A>G NM_004453.2
ETFDH Chr4:159602711 c.176-636C>G NM_004453.2
ETHE1 Chr19:44031407 NM_014297.3
GAMT Chr19:1399508 c.391+15G>T NM_138924.2 rs367567416
GCDH Chr19:13010271 c.1244-11A>G NM_000159.3
GCH1 Chr14:55369403 c.-22C>T NM_000161.2
L2HGDH Chr14:50735527 c.906+354G>A NM_024884.2
MOCS1 Chr6:39874534 c.*365_*366delAG NM_005943.5 rs397518419
MOCS1 Chr6:39876810 c.*7+6T>C NM_005943.5
MOCS1 Chr6:39894006 c.251-418delT NM_005943.5
MTHFR Chr1:11850973 c.1753-18G>A NM_005957.4 rs777661576
MTHFR Chr1:11863212 c.-13-28_-13-27delCT NM_005957.4 rs786204005
PGK1 ChrX:77381262 c.1214-25T>G NM_000291.3
PTS Chr11:112098994 c.84-323A>T NM_000317.2 rs794726657
PTS Chr11:112099026 c.84-291A>G NM_000317.2
PTS Chr11:112100215 c.164-716A>T NM_000317.2
PTS Chr11:112101310 c.187-38dupG NM_000317.2
QDPR Chr4:17500790 c.436+2552A>G NM_000320.2
SERAC1 Chr6:158576548 c.92-165C>T NM_032861.3
SERAC1 Chr6:158576622 c.92-239G>C NM_032861.3
SLC2A1 Chr1:43395462 c.680-11G>A NM_006516.2
SLC2A1 Chr1:43424429 c.-107G>A NM_006516.2

Added and removed genes from the panel

Genes added Genes removed
MT-ATP6
MT-ATP8
MT-CO1
MT-CO2
MT-CO3
MT-CYB
MT-ND1
MT-ND2
MT-ND3
MT-ND4
MT-ND4L
MT-ND5
MT-ND6
MT-RNR1
MT-RNR2
MT-TA
MT-TC
MT-TD
MT-TE
MT-TF
MT-TG
MT-TH
MT-TI
MT-TK
MT-TL1
MT-TL2
MT-TM
MT-TN
MT-TP
MT-TQ
MT-TR
MT-TS1
MT-TS2
MT-TT
MT-TV
MT-TW
MT-TY

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
  • Our publicly available analytic validation demonstrating complete details of test performance
  • ~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

The following exons are not included in the panel as they are not sufficiently covered with high quality sequence reads: SLC39A8 (NM_001135148:1). Genes with suboptimal coverage in our assay are marked with number sign (#) and genes with partial, or whole gene, segmental duplications in the human genome are marked with an asterisk (*) if they overlap with the UCSC pseudogene regions. Gene is considered to have suboptimal coverage when >90% of the gene’s target nucleotides are not covered at >20x with mapping quality score (MQ>20) reads. The technology may have limited sensitivity to detect variants in genes marked with these symbols (please see the Panel content table above).

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 and see our Analytic Validation.

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.

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

Bioinformatics

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.

Clinical interpretation

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 corner stone 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 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 health care provider at no additional cost.

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