- Is a 32 gene panel that includes assessment of non-coding variants
Is ideal for patients with a clinical suspicion of hypophosphatasia or hypophosphatemic rickets. The genes on this panel are included in the Comprehensive Growth Disorders / Skeletal Dysplasias and Disorders Panel.
The Blueprint Genetics Skeletal Dysplasia with Abnormal Mineralization Panel (test code MA1301):
Commonly used ICD-10 code(s) when ordering the Skeletal Dysplasia with Abnormal Mineralization Panel
- 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.
Note that we do not accept DNA samples isolated from formalin-fixed paraffin-embedded (FFPE) tissue. Read more about our sample requirements here.
Hypophosphatasia is a rare inherited skeletal dysplasia due to loss of function mutations in the ALPL gene. It is characterized by defective mineralization of bone and/or teeth in the presence of low activity of serum and bone alkaline phosphatase. Clinical features range from stillbirth without mineralized bone at the severe end to pathologic fractures of the lower extremities in later adulthood at the mild end. At least six clinical forms are currently recognized based on age at diagnosis and severity of features. The differential diagnosis of hypophosphatasia depends on the age at which the diagnosis is considered. In utero, osteogenesis imperfecta (OI) type II and campomelic dysplasia are the most common differential diagnoses. Rare conditions such as Stuve–Wiedemann syndrome may also be involved. At birth, OI type II, campomelic dysplasia, and chondrodysplasias with bone mineralization defect are very similar diseases and are challenging to differentiate radiographically. In infancy and childhood, different OI types are the most common differential diagnosis, but rarer disorders such as cleidocranial dysostosis, Cole-Carpenter syndrome, idiopathic juvenile osteoporosis, and renal osteodystrophy should be considered. In adulthood, osteopenia/osteoporosis and more rarely osteoarthritis and pseudogout may be caused by hypophosphatasia. Serum alkaline phosphatase activity can suggest the diagnosis pending confirmation with genetic testing. Hypophosphatemic rickets (HR) is a genetic disorder which prevents sufficient reabsorption of phosphate in the proximal renal tubule, with increased phosphate excretion, resulting in rickets. Rickets is a metabolic disorder of the growing bone which occurs in children before fusion of the epiphysis and is characterized by impaired mineralization of the osteoid matrix during growth. The most common form of HR is inherited in an X-linked manner, but the remaining 20% of familial HR patients belong to the autosomal dominant HR and to the hereditary HR with calciuria types.
Genes in the Skeletal Dysplasia with Abnormal Mineralization Panel and their clinical significance
|ALPL||Odontohypophosphatasia, Hypophosphatasia perinatal lethal, infantile, juvenile and adult forms||AD/AR||78||291|
|ANKH||Calcium pyrophosphate deposition disease (familial chondrocalcinosis type 2), Craniometaphyseal dysplasia autosomal dominant type||AD||13||20|
|B4GALT7||Ehlers-Danlos syndrome, progeroid form||AR||8||9|
|CASR||Hypocalcemia, Neonatal hyperparathyroidism, Familial Hypocalciuric hypercalcemia with transient Neonatal hyperparathyroidism||AD/AR||104||396|
|CLCN5||Proteinuria, low molecular weight, with hypercalciuric nephrocalcinosis, Hypophosphatemic rickets,, Nephrolithiasis, I, Dent disease||XL||48||272|
|COL1A1||Ehlers-Danlos syndrome, Caffey disease, Osteogenesis imperfecta type 1, Osteogenesis imperfecta type 2, Osteogenesis imperfecta type 3, Osteogenesis imperfecta type 4||AD||352||962|
|COL1A2||Ehlers-Danlos syndrome, cardiac valvular form, Osteogenesis imperfecta type 1, Osteogenesis imperfecta type 2, Osteogenesis imperfecta type 3, Osteogenesis imperfecta type 4||AD/AR||186||509|
|CRTAP||Osteogenesis imperfecta type 2, Osteogenesis imperfecta type 3, Osteogenesis imperfecta type 4||AR||12||30|
|CYP27B1||Vitamin D-dependent rickets||AR||23||73|
|ENPP1||Arterial calcification, Hypophosphatemic rickets||AR||22||72|
|FBN1||MASS syndrome, Marfan syndrome, Acromicric dysplasia, Geleophysic dysplasia||AD||1465||2679|
|FGF23||Tumoral calcinosis, hyperphosphatemic, Hypophosphatemic rickets||AD/AR||10||17|
|FKBP10||Bruck syndrome 1, Osteogenesis imperfecta, type XI||AR||20||44|
|GALNT3||Tumoral calcinosis, hyperphosphatemic||AR||17||35|
|PLOD2||Bruck syndrome, Osteogenesis imperfecta type 3||AR||8||23|
|PLS3||Osteoporosis and osteoporotic fractures||XL||1||17|
|PPIB||Osteogenesis imperfecta type 2, Osteogenesis imperfecta type 3, Osteogenesis imperfecta type 4||AR||8||13|
|PTDSS1||Lenz-Majewski hyperostotic dwarfism||AD||5||7|
|SERPINF1||Osteogenesis imperfecta, type VI||AR||9||41|
|SLC34A3||Hypophosphatemic rickets with hypercalciuria||AR||22||38|
|SLC39A13||Spondylodysplastic Ehlers-Danlos syndrome||AR||2||9|
|SNX10||Osteopetrosis, autosomal recessive 8||AR||3||13|
|SOX9||Campomelic dysplasia, 46,XY sex reversal, Brachydactyly with anonychia (Cooks syndrome)||AD||47||144|
|TNFRSF11A||Familial expansile osteolysis, Paget disease of bone, Osteopetrosis, severe neonatal or infantile forms (OPTB1)||AD/AR||8||24|
|TNFRSF11B||Paget disease of bone, juvenile||AR||8||18|
|VDR||Vitamin D-dependent rickets||AD/AR||17||66|
Gene refers to the HGNC approved gene symbol; Inheritance refers to inheritance patterns such as autosomal dominant (AD), autosomal recessive (AR), 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 Orphanet databases.
Non-coding variants covered by Skeletal Dysplasia with Abnormal Mineralization Panel
|Gene||Genomic location HG19||HGVS||RefSeq||RS-number|
|IFITM5||Chr11:299504||c.-14C>T||NM_001025295.2||rs587776916||Explain almost all cases of OI type V||PMID 23240094|
- CAP and ISO-15189 accreditations covering all operations at Blueprint Genetics including all Whole Exome Sequencing, NGS panels and confirmatory testing
- 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
- Our Nucleus online portal providing transparent and easy access to quality and performance data at the patient level
- Our publically available analytic validation demonstrating complete details of test performance
- ~1,500 non-coding disease causing variants in Blueprint WES assay (please see below ‘Non-coding disease causing variants covered by this panel’)
- Our rigorous variant classification based on modified ACMG variant classification scheme
- Our systematic clinical interpretation workflow using proprietary software enabling accurate and traceable processing of NGS data
- Our comprehensive clinical statements
- Complex inversions
- Gene conversions
- Balanced translocations
- Mitochondrial DNA variants
- 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).
- Low level mosaicism (variant with a minor allele fraction of 14.6% is detected with 90% probability)
- Stretches of mononucleotide repeats
- Indels larger than 50bp
- Single exon deletions or duplications
- Variants within pseudogene regions/duplicated segments
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 Blueprint Genetics skeletal dysplasia with abnormal mineralization panel covers classical genes associated with hypophosphatasia, hypophosphatemic rickets and osteogenesis imperfecta. The genes on the panel have been carefully selected based on scientific literature, mutation databases and our experience.
Our panels are sliced from our high-quality whole exome sequencing data. Please see our sequencing and detection performance table for different types of alterations at the whole exome level (Table).
Assays have been validated for different starting materials including EDTA-blood, isolated DNA (no FFPE), saliva and dry blood spots (filter card) and all provide high-quality results. The diagnostic yield varies substantially depending on the assay used, referring healthcare professional, hospital and country. Blueprint Genetics’ Plus Analysis (Seq+Del/Dup) maximizes the chance to find a molecular genetic diagnosis for your patient although Sequence Analysis or Del/Dup Analysis may be a cost-effective first line test if your patient’s phenotype is suggestive of a specific mutation type.
Performance of Blueprint Genetics Whole Exome Sequencing (WES) assay. All individual panels are sliced from WES data.
|Sensitivity % (TP/(TP+FN)||Specificity %|
|Single nucleotide variants||99.65% (412,456/413,893)||>99.99%|
|Insertions, deletions and indels by sequence analysis|
|1-10 bps||96.94% (17,070/17,608)||>99.99%|
|11-50 bps||99.07% (957/966)||>99.99%|
|Copy number variants (exon level dels/dups)|
|Clinical samples (small CNVs, n=52)|
|1 exon level deletion||92.3% (24/26)||NA|
|2 exons level deletion/duplication||100.0% (11/11)||NA|
|3-7 exons level deletion/duplication||93.3% (14/15)||NA|
|Microdeletion/-duplication sdrs (large CNVs, n=37))|
|Size range (0.1-47 Mb)||100% (37/37)|
|Simulated CNV detection|
|2 exons level deletion/duplication||90.98% (7,357/8,086)||99.96%|
|5 exons level deletion/duplication||98.63% (7,975/8,086)||99.98%|
|The performance presented above reached by WES with the following coverage metrics|
|Mean sequencing depth at exome level||174x|
|Nucleotides with >20x sequencing coverage (%)||99.4%|
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 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. 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 such as, 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, the customer has an access to details of the analysis, including patient specific sequencing metrics, a gene level coverage plot and a list of regions with inadequate coverage if present. This reflects our mission to build fully transparent diagnostics where customers have easy access to 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 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 variants classified as pathogenic, likely pathogenic and variants of uncertain significance
(VUS) are confirmed using bi-directional Sanger sequencing when they do not meet our stringent NGS quality metrics for a true positive call.
Reported copy number variations with a size <10 exons are confirmed by orthogonal methods such as qPCR if the specific CNV has been seen less than three times at Blueprint Genetics (Plus analysis only).
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 used, congress abstracts and mutation databases to help our customers 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 within the family. In the case of variants of uncertain significance (VUS), we do not recommend family member risk stratification based on the VUS result. Furthermore, in the case of VUS, we do not recommend the use of genetic information in patient management or genetic counseling.
Our interpretation team analyzes millions of variants from thousands of individuals with rare diseases. Thus, our database, and our understanding of variants and related phenotypes, is growing by leaps and bounds. 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.