MODY Panel

Updated
Summary
  • Is a 52 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 maturity onset diabetes of the young (MODY).

Analysis methods
  • PLUS
Availability

4 weeks

Number of genes

52

Test code

EN0601

Panel size

Large

CPT code *
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 MODY Panel (test code EN0601):

ICD codes

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

ICD-10 Disease
F84.2 Rett syndrome
E11.9 Maturity-onset diabetes of the young
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 (Oragene DNA OG-500 kit/OGD-500 or OG-575 & OGD-575)

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.

Maturity-onset diabetes of the young (MODY) is an autosomal dominant inherited form of diabetes and accounts for 1–2% of individuals with diabetes. MODY is a rare clinically and genetically heterogeneous form of diabetes characterized by young age of onset (generally 10-45 years of age), with development of non-insulin dependent diabetes prior to 25 years of age. Additionally, blood vessel abnormalities of the retinas (retinopathy) and kidneys, and congenital abnormalities due to diabetes complications have also been noted. Individuals with MODY typically have no reported history of obesity or metabolic syndrome accompanying hyperglycemia. Many people with MODY are misdiagnosed with type 1 or type 2 diabetes. MODY is the most common form of monogenic diabetes with an estimated prevalence at 1:10,000 in adults and 1:23,000 in children. Approximately 80% of cases are misdiagnosed as type 1 or type 2 diabetes, complicating prevalence and incidence estimations. Genetic testing is generally pursued only in those with classic features of MODY. However, only 50% of subjects with genetically diagnosed MODY meet classic criteria. Establishing a diagnosis of MODY significantly impacts clinical management. Heterozygous mutations in HNF1A, HNF4A, and GCK account for >90% of all MODY with a known genetic cause. Patients with HNF1A and HNF4A mutations have slowly progressing beta-cell dysfunction, and treatment with low-dose sulfonylurea results in stable or improved glycemic control and improved quality of life related to diabetes care compared with insulin or metformin therapy. GCK-MODY has a unique phenotype of mild, nonprogressive hyperglycemia, with HbA1c typically <7% (53 mmol/mol). It is not associated with increased risk of microvascular and macrovascular complications seen in other forms of diabetes. Generally, treatment does not change HbA1c. Molecular diagnosis of GCK-MODY allows pharmacologic therapy to be discontinued and decreases the frequency of medical surveillance. (PMID: 24026547).

Genes in the MODY Panel and their clinical significance

Gene Associated phenotypes Inheritance ClinVar HGMD
ABCC8 Hyperinsulinemic hypoglycemia, Diabetes, permanent neonatal, Hypoglycemia, leucine-induced, Diabetes mellitus, transient neonatal, Pulmonary arterial hypertension (PAH) AD/AR 170 641
APPL1 Maturity-onset diabetes of the young, type 14 AD 2 2
BLK Maturity onset diabetes of the young AD 5 9
CEL* Maturity-onset diabetes of the young, type 8 AD 4 13
GCK Hyperinsulinemic hypoglycemia, familial, Diabetes mellitus, permanent neonatal, Maturity-onset diabetes of the young, type 2 AD/AR 178 837
HNF1A Maturity onset diabetes of the young, Renal cell carcinoma, nonpapillary clear cell, Liver adenomatosis AD 78 528
HNF1B Renal cell carcinoma, nonpapillary chromophobe, Renal cysts and diabetes syndrome AD 35 234
HNF4A Congenital hyperinsulinism, diazoxide-responsive, Maturity onset diabetes of the young, Fanconi renotubular syndrome 4 with maturity-onset diabetes of the young AD 32 147
INS Diabetes mellitus, permanent neonatal, Hyperproinsulinemia, familial, with or without diabetes, Maturity onset diabetes of the young AD 33 78
KCNJ11 Hyperinsulinemic hypoglycemia, Diabetes, permanent neonatal, Diabetes mellitus, transient neonatal, Maturity-onset diabetes of the young 13, Paternally-inherited mutations can cause Focal adenomatous hyperplasia AD/AR 63 178
KLF11 Maturity onset diabetes of the young AD 1 4
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 Leber hereditary optic neuropathy 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 Leber hereditary optic neuropathy, Mitochondrial multisystemic disorder, Progressive external ophthalmoplegia, Dilated cardiomyopathy (DCM) Mitochondrial 4
MT-TC Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes Mitochondrial 3
MT-TD Mitochondrial multisystemic disorder 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 Hypertrophic cardiomyopathy, Encephalopathy, Myopathy Mitochondrial 3
MT-TH Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes Mitochondrial 4
MT-TI Progressive external ophthalmoplegia Mitochondrial 7
MT-TK Myoclonic epilepsy with ragged red fibers 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 Progressive external ophthalmoplegia, Mitochondrial multisystemic disorder Mitochondrial 5
MT-TM Mitochondrial Myopathy, Leigh syndrome, Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes Mitochondrial 1
MT-TN Progressive external ophthalmoplegia Mitochondrial 3
MT-TP Mitochondrial multisystemic disorder Mitochondrial 2
MT-TQ Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes, Encephalopathy Mitochondrial 2
MT-TR Dilated cardiomyopathy (DCM) 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 Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes Mitochondrial 3
MT-TW Leigh syndrome, Mitochondrial Myopathy Mitochondrial 8
MT-TY Mitochondrial 4
NEUROD1 Maturity onset diabetes of the young AD 3 18
PAX4 Diabetes mellitus AD 3 10
PDX1 Pancreatic agenesis, Neonatal diabetes mellitus, Maturity-onset diabetes of the young, type 4, Lactic acidemia due to PDX1 deficiency AD/AR 10 28
RFX6 Pancreatic hypoplasia, intestinal atresia, and gallbladder aplasia or hypoplasia, with or without tracheoesophageal fistula, Martinez-Frias syndrome, Mitchell-Riley syndrome AR 10 31

* 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 MODY Panel

Gene Genomic location HG19 HGVS RefSeq RS-number
ABCC8 Chr11:17415959 c.4412-13G>A NM_000352.3 rs1008906426
ABCC8 Chr11:17427028 c.3399+13G>A NM_000352.3 rs182340196
ABCC8 Chr11:17449501 c.2041-12C>A NM_000352.3
ABCC8 Chr11:17449510 c.2041-21G>A NM_000352.3 rs746714109
ABCC8 Chr11:17449514 c.2041-25G>A NM_000352.3
ABCC8 Chr11:17452526 c.1672-20A>G NM_000352.3
ABCC8 Chr11:17465872 c.1333-1013A>G NM_000352.3
ABCC8 Chr11:17470268 c.1177-53_1177-51delGTG NM_000352.3 rs1271038564
ABCC8 Chr11:17498513 c.-190C>G NM_000352.3
BLK Chr8:11422122 c.*505G>T NM_001715.2
GCK Chr7:44186044 c.1022+18G>A NM_033507.1 rs150914617
GCK Chr7:44193073 c.49-15_49-11delCCCCTinsGGGAGGG NM_033507.1
GCK Chr7:44229009 c.-457C>T NM_000162.3 rs548039601
GCK Chr7:44229109 c.-557G>C NM_000162.3
HNF1A Chr12:121416034 c.-538G>C NM_000545.5
HNF1A Chr12:121416110 c.-462G>A NM_000545.5
HNF1A Chr12:121416281 c.-291T>C NM_000545.5 rs534474388
HNF1A Chr12:121416285 c.-287G>A NM_000545.5
HNF1A Chr12:121416285 NM_000545.5
HNF1A Chr12:121416289 c.-283A>C NM_000545.5
HNF1A Chr12:121416314 c.-258A>G NM_000545.5 rs756136537
HNF1A Chr12:121416354 c.-218T>C NM_000545.5
HNF1A Chr12:121416385 c.-187C>A/T NM_000545.5
HNF1A Chr12:121416385 NM_000545.5
HNF1A Chr12:121416385 NM_000545.5 rs970766228
HNF1A Chr12:121416391 NM_000545.5
HNF1A Chr12:121416437 NM_000545.5
HNF1A Chr12:121416446 NM_000545.5 rs780586155
HNF1A Chr12:121416453 c.-119G>A NM_000545.5 rs371945966
HNF1A Chr12:121416475 c.-97T>G NM_000545.5
HNF1A Chr12:121416508 NM_000545.5
HNF4A Chr20:42984253 c.-192C>G NM_175914.4
HNF4A Chr20:42984264 c.-181G>A NM_175914.4
HNF4A Chr20:42984271 c.-174T>C NM_175914.4
HNF4A Chr20:42984276 c.-169C>T NM_175914.4
HNF4A Chr20:42984299 c.-146T>C NM_175914.4
HNF4A Chr20:42984309 c.-136A>G NM_175914.4
HNF4A Chr20:43036000 c.291-21A>G NM_000457.4
INS Chr11:2181023 c.*59A>G NM_000207.2 rs397515519
INS Chr11:2181242 c.188-15G>A NM_000207.2 rs574629011
INS Chr11:2181258 c.188-31G>A NM_000207.2 rs797045623
INS Chr11:2181774 c.187+241G>A NM_000207.2
INS Chr11:2182419 c.-39A>C NM_000207.2
INS Chr11:2182532 c.-152C>G NM_000207.2 rs748749585
INS Chr11:2182532 c.-152C>A NM_000207.2
INS Chr11:2182533 c.-153C>G NM_000207.2
INS Chr11:2182543 c.-187_-164del NM_000207.2
KCNJ11 Chr11:17409692 c.-54C>T NM_000525.3
KCNJ11 Chr11:17409772 c.-134G>T NM_000525.3 rs387906398
NEUROD1 Chr2:182545307 c.-162G>A NM_002500.4 rs537184640
RFX6 Chr6:117198947 c.224-12A>G NM_173560.3

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

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. 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 96.9% (7,563/7,806) >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% (37/37)
     
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 % (TP/(TP+FN) 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=2084 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%) 88.7% (47/53) 99.93%
Insertions and deletions by sequence analysis n=42 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) >0.9999
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 Blueprint Genetics Variant Classification Schemes based on the ACMG guideline 2015. Minor modifications were made to increase reproducibility of the variant classification and improve the clinical validity of the report. Our experience with tens of thousands of clinical cases analyzed at our laboratory allowed us to further develop the industry standard.

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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