Neuronal Migration Disorder Panel

Summary
Is a 59 gene panel that includes assessment of non-coding variants.

Is ideal for patients with a clinical suspicion of neuronal migration disorder.

Analysis methods
  • PLUS
Availability
4 weeks
Number of genes
59
Test code
MA2601
Panel tier
Tier 2
CPT Code *
81403, 81404, 81405 x5, 81406 x2, 81407 x2, 81408 x2, 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 Neuronal Migration Disorder Panel (test code MA2601):

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.

Neuronal migration disorders (NMDs) are a group of birth defects caused by the abnormal migration of neurons in the developing brain and nervous system. During development, neurons must migrate from the areas where they are originate to the areas where they will settle into their proper neural circuits. The structural abnormalities found in NMDs include schizencephaly, porencephaly, lissencephaly, agyria, macrogyria, polymicrogyria, pachygyria, microgyria, micropolygyria, neuronal heterotopias, agenesis of the corpus callosum, and agenesis of the cranial nerves. Mutations of many genes are involved in neuronal migration disorders, such as DCX in classical lissencephaly spectrum, TUBA1A in microlissencephaly with agenesis of the corpus callosum, and RELN and VLDLR in lissencephaly with cerebellar hypoplasia. Mutations in ARX cause a variety of phenotypes ranging from hydranencephaly or lissencephaly to early-onset epileptic encephalopathies, including Ohtahara syndrome and infantile spasms or intellectual disability with no brain malformations.

Genes in the Neuronal Migration Disorder Panel and their clinical significance

To view complete table content, scroll horizontally.

Gene Associated phenotypes Inheritance ClinVar HGMD
ACTB* Baraitser-Winter syndrome AD 55 60
ACTG1* Deafness, Baraitser-Winter syndrome AD 27 47
ADGRG1 Polymicrogyria, bilateral frontoparietal, Polymicrogyris, bilateral perisylvian AR 27 35
AKT3 Megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome AD 13 28
ARFGEF2 Heterotopia, periventricular AR 7 13
ARX# Lissencephaly, Epileptic encephalopathy, Corpus callosum, agenesis of, with abnormal genitalia, Partington syndrome, Proud syndrome, Hydranencephaly with abnormal genitalia, Intellectual developmental disorder XL 66 93
ATP6V0A2 Cutis laxa, Wrinkly skin syndrome AR 16 56
B3GALNT2# Muscular dystrophy-dystroglycanopathy AR 18 14
COL4A1 Schizencephaly, Anterior segment dysgenesis with cerebral involvement, Retinal artery tortuosity, Porencephaly, Angiopathy, hereditary, with nephropathy, aneurysms, and muscle cramps, Brain small vessel disease AD 58 107
COL4A2 Hemorrhage, intracerebral AD 14 12
DCX Lissencephaly, Subcortical laminal heterotopia XL 131 142
DYNC1H1 Spinal muscular atrophy, Charcot-Marie-Tooth disease, Intellectual developmental disorder AD 60 71
EMX2 Schizencephaly AD 4 6
FAT4 Van Maldergem syndrome 2 AR 13 33
FH Hereditary leiomyomatosis and renal cell cancer, Fumarase deficiency AD/AR 178 207
FKTN Muscular dystrophy-dystroglycanopathy, Dilated cardiomyopathy (DCM), Muscular dystrophy-dystroglycanopathy (limb-girdle) AR 45 58
FLNA Frontometaphyseal dysplasia, Osteodysplasty Melnick-Needles, Otopalatodigital syndrome type 1, Otopalatodigital syndrome type 2, Terminal osseous dysplasia with pigmentary defects, Periventricular nodular heterotopia 1, Melnick-Needles syndrome, Intestinal pseudoobstruction, neuronal, X-linked/Congenital short bowel syndrome, Cardiac valvular dysplasia, X-linked XL 133 257
FLVCR2 Proliferative vasculopathy and hydraencephaly-hydrocephaly syndrome AR 9 17
GMPPB Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), Limb-girdle muscular dystrophy-dystroglycanopathy AR 19 41
GPSM2 Deafness, Chudley-McCullough syndrome AR 18 11
ISPD Muscular dystrophy-dystroglycanopathy AR 38 53
KATNB1 Lissencephaly 6, with microcephaly AR 6 10
KIF1BP Goldberg-Shprintzen megacolon syndrome AR 7 10
KIF7 Acrocallosal syndrome, Hydrolethalus syndrome, Al-Gazali-Bakalinova syndrome, Joubert syndrome AR/Digenic 24 44
L1CAM Mental retardation, aphasia, shuffling gait, and adducted thumbs (MASA) syndrome, Hydrocephalus due to congenital stenosis of aqueduct of Sylvius, Spastic, CRASH syndrome, Corpus callosum, partial agenesis XL 80 292
LAMA2 Muscular dystrophy, congenital merosin-deficient AR 199 301
LAMB1 Lissencephaly 5 AR 8 7
LAMC3 Cortical malformations, occipital AR 8 16
LARGE Muscular dystrophy-dystroglycanopathy AR 19 27
MACF1 Lissencephaly AD 1 9
MED12 Ohdo syndrome, Intellectual disability with Marfanoid habitus, FG syndrome, Opitz-Kaveggia syndrome, Lujan-Fryns syndrome XL 29 30
MEF2C Intellectual developmental disorder AD 45 84
MPDZ Hydrocephalus, nonsyndromic, autosomal recessive 2 AR 14 24
NDE1 Microhydranencephaly, Lissencephaly AR 13 18
NSDHL Congenital hemidysplasia with ichthyosiform erythroderma and limb defects (CHILD syndrome), CK syndrome XL 15 28
OCLN#* Pseudo-TORCH syndrome 1 (Band-like calcification with simplified gyration and polymicrogyria) AR 13 20
PAFAH1B1 Lissencephaly, Subcortical laminar heterotopia AD 121 169
PHGDH Neu-Laxova syndrome 1 AR 13 23
PIK3CA* Cowden syndrome, CLOVES AD 85 56
PIK3R2 Megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 1 AD 8 8
POMGNT2 Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A, 8 AR 6 9
POMT1 Muscular dystrophy-dystroglycanopathy AR 47 96
RAB18 Warburg micro syndrome 3 AR 5 5
RAB3GAP1 Warburg micro syndrome AR 29 66
RAB3GAP2 Warburg micro syndrome, Martsolf syndrome AR 11 15
RELN Lissencephaly, Epilepsy, familial temporal lobe AD/AR 25 44
RTTN Microcephaly, short stature, and polymicrogyria with or without seizures AR 16 16
SEPSECS Pontocerebellar hypoplasia, type 2D AR 10 15
SRPX2 ?Rolandic epilepsy, impaired intellectual development, and speech dyspraxia XL 3 4
TMEM5 Muscular dystrophy-dystroglycanopathy AR 11 7
TUBA1A* Lissencephaly AD 69 65
TUBA8 Polymicrogyria with optic nerve hypoplasia AR 1 3
TUBB2A#* Cortical dysplasia, complex, with other brain malformations 5 AD 12 5
TUBB2B#* Polymicrogyria, asymmetric AD 21 30
TUBB3* Fibrosis of extraocular muscles, congenital, Cortical dysplasia, complex, with other brain malformations AD/AR 28 25
TUBG1* Cortical dysplasia, complex, with other brain malformations 4 AD 5 3
VLDLR Cerebellar ataxia, mental retardation, and dysequilibrium syndrome AR 11 24
WDR62 Microcephaly AR 33 48
YWHAE Distal 17p13.3 microdeletion syndrome, Endometrial stromal sarcoma, 17p13.3 microduplication syndrome, Miller-Dieker syndrome AD/AR 12 44
#

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.

*

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

The sensitivity to detect variants may be limited in genes marked with an asterisk (*) or number sign (#). Due to possible limitations these genes may not be available as single gene tests.

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 Neuronal Migration Disorder Panel

To view complete table content, scroll horizontally.

Gene Genomic location HG19 HGVS RefSeq RS-number
ADGRG1 Chr16:57673285 c.-435_-421delCAACGGTTGCCAGGG NM_001145774.1
COL4A1 Chr13:110802675 c.*35C>A NM_001845.4
COL4A1 Chr13:110802678 c.*32G>A/T NM_001845.4
COL4A1 Chr13:110802679 c.*31G>T NM_001845.4
FKTN Chr9:108368857 c.648-1243G>T NM_006731.2
FLNA ChrX:153581587 c.6023-27_6023-16delTGACTGACAGCC NM_001110556.1
GMPPB Chr3:49761246 c.-87C>T NM_013334.3 rs780961444
L1CAM ChrX:153128846 c.3531-12G>A NM_000425.4
L1CAM ChrX:153131293 c.2432-19A>C NM_000425.4
L1CAM ChrX:153133652 c.1704-75G>T NM_000425.4
L1CAM ChrX:153133926 c.1547-14delC NM_000425.4
L1CAM ChrX:153136500 c.523+12C>T NM_000425.4
LAMA2 Chr6:129633984 c.3175-22G>A NM_000426.3 rs777129293
LAMA2 Chr6:129636608 c.3556-13T>A NM_000426.3 rs775278003
LAMA2 Chr6:129714172 c.5235-18G>A NM_000426.3 rs188365084
LAMA2 Chr6:129835506 c.8989-12C>G NM_000426.3 rs144860334
MEF2C Chr5:88179125 c.-510_-497delTCTTCCTCCTCCTC NM_002397.4
NSDHL ChrX:152037789 c.*129C>T NM_015922.2 rs145978994
POMT1 Chr9:134379574 c.-30-2A>G NM_007171.3
RTTN Chr18:67727297 c.4748-19T>A NM_173630.3
RTTN Chr18:67815044 c.2309+1093G>A NM_173630.3
TUBA8 Chr22:18604221 c.4-21_4-8delGTTGCTTCCCTCTC NM_018943.2
YWHAE Chr17:1303862 c.-458G>T NM_006761.4

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

The following exons are not included in the panel as they are not sufficiently covered with high quality sequence reads: *B3GALNT2* (NM_001277155:2), *OCLN* (NM_002538:5,7,8). 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.

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.