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Invitae Hereditary Multiple Osteochondromas Panel

Test code: 04614 •

Test description

The Invitae Hereditary Multiple Osteochondromas Panel analyzes up to 3 genes that are associated with hereditary multiple osteochondromas (HMO), which is characterized by multiple cartilage-capped bone growths (known as osteochondromas or osteocartilaginous exostoses) arising from the growth plate area in the juxta-epiphyseal region of long tubular bones or from the surface of flat bones.

Genetic testing of these genes may confirm a diagnosis and help guide treatment and management decisions. Identification of a disease-causing variant can inform recurrence-risk assessment and genetic counseling.

Disorders tested

  • hereditary multiple osteochondromas (HMO)

Ordering information

Turnaround time:

10–21 calendar days (14 days on average)

New York approved:

Yes

Preferred specimen:

3mL whole blood in a purple-top EDTA tube (K2EDTA or K3EDTA)

Alternate specimens:

Saliva, buccal swab, and gDNA are also accepted.Learn more about specimen requirementsRequest a specimen collection kit

Clinical description and sensitivity

Clinical description:

HMO is a skeletal disease characterized by multiple cartilage-capped bone growths, known as osteochondromas or osteocartilaginous exostoses, arising from the growth plate area in the juxta-epiphyseal region of long tubular bones or from the surface of flat bones. Most lesions appear in children and adolescents as painless, slow-growing masses, which increase in size and number until the growth plates close when skeletal maturation is achieved at the end of puberty. There is significant inter- and intrafamilial phenotypic variability, including variation in the number and size of osteochondromas, the number and location of involved bones, and the degree of deformities. These tumors mainly occur on the distal femur (90%), and the proximal tibia (84%), fibula (76%), and humerus (72%). Although osteochondromas are benign tumors, they may cause secondary complications including fracture, bony deformity, mechanical joint problems, and compression of nerves, tendons, and blood vessels. Osteochondromas are often accompanied by short stature. The most serious complication is the malignant transformation of an osteochondroma toward a secondary peripheral chondrosarcoma, occurring in 1–5% of patients, the risk of which increases with age.

Clinical description and sensitivity

Clinical description:

HMO is a skeletal disease characterized by multiple cartilage-capped bone growths, known as osteochondromas or osteocartilaginous exostoses, arising from the growth plate area in the juxta-epiphyseal region of long tubular bones or from the surface of flat bones. Most lesions appear in children and adolescents as painless, slow-growing masses, which increase in size and number until the growth plates close when skeletal maturation is achieved at the end of puberty. There is significant inter- and intrafamilial phenotypic variability, including variation in the number and size of osteochondromas, the number and location of involved bones, and the degree of deformities. These tumors mainly occur on the distal femur (90%), and the proximal tibia (84%), fibula (76%), and humerus (72%). Although osteochondromas are benign tumors, they may cause secondary complications including fracture, bony deformity, mechanical joint problems, and compression of nerves, tendons, and blood vessels. Osteochondromas are often accompanied by short stature. The most serious complication is the malignant transformation of an osteochondroma toward a secondary peripheral chondrosarcoma, occurring in 1–5% of patients, the risk of which increases with age.


Clinical sensitivity:


Full gene sequencing and duplication/deletion analysis are expected to identify pathogenic variants in 85 to 95 percent of affected individuals.

Assay information

Invitae is a College of American Pathologists (CAP)-accredited and Clinical Laboratory Improvement Amendments (CLIA)-certified clinical diagnostic laboratory performing full-gene sequencing and deletion/duplication analysis using next-generation sequencing technology (NGS).

Our sequence analysis covers clinically important regions of each gene, including coding exons and 10 to 20 base pairs of adjacent intronic sequence on either side of the coding exons in the transcript listed below, depending on the specific gene or test. In addition, the analysis covers select non-coding variants. Any variants that fall outside these regions are not analyzed. Any limitations in the analysis of these genes will be listed on the report. Contact client services with any questions.

Based on validation study results, this assay achieves >99% analytical sensitivity and specificity for single nucleotide variants, insertions and deletions <15bp in length, and exon-level deletions and duplications. Invitae's methods also detect insertions and deletions larger than 15bp but smaller than a full exon but sensitivity for these may be marginally reduced. Invitae’s deletion/duplication analysis determines copy number at a single exon resolution at virtually all targeted exons. However, in rare situations, single-exon copy number events may not be analyzed due to inherent sequence properties or isolated reduction in data quality. Certain types of variants, such as structural rearrangements (e.g. inversions, gene conversion events, translocations, etc.) or variants embedded in sequence with complex architecture (e.g. short tandem repeats or segmental duplications), may not be detected. Additionally, it may not be possible to fully resolve certain details about variants, such as mosaicism, phasing, or mapping ambiguity. Unless explicitly guaranteed, sequence changes in the promoter, non-coding exons, and other non-coding regions are not covered by this assay. Please consult the test definition on our website for details regarding regions or types of variants that are covered or excluded for this test. This report reflects the analysis of an extracted genomic DNA sample. In very rare cases, (circulating hematolymphoid neoplasm, bone marrow transplant, recent blood transfusion) the analyzed DNA may not represent the patient's constitutional genome.

Assay information

Invitae is a College of American Pathologists (CAP)-accredited and Clinical Laboratory Improvement Amendments (CLIA)-certified clinical diagnostic laboratory performing full-gene sequencing and deletion/duplication analysis using next-generation sequencing technology (NGS).

Our sequence analysis covers clinically important regions of each gene, including coding exons and 10 to 20 base pairs of adjacent intronic sequence on either side of the coding exons in the transcript listed below, depending on the specific gene or test. In addition, the analysis covers select non-coding variants. Any variants that fall outside these regions are not analyzed. Any limitations in the analysis of these genes will be listed on the report. Contact client services with any questions.

Based on validation study results, this assay achieves >99% analytical sensitivity and specificity for single nucleotide variants, insertions and deletions <15bp in length, and exon-level deletions and duplications. Invitae's methods also detect insertions and deletions larger than 15bp but smaller than a full exon but sensitivity for these may be marginally reduced. Invitae’s deletion/duplication analysis determines copy number at a single exon resolution at virtually all targeted exons. However, in rare situations, single-exon copy number events may not be analyzed due to inherent sequence properties or isolated reduction in data quality. Certain types of variants, such as structural rearrangements (e.g. inversions, gene conversion events, translocations, etc.) or variants embedded in sequence with complex architecture (e.g. short tandem repeats or segmental duplications), may not be detected. Additionally, it may not be possible to fully resolve certain details about variants, such as mosaicism, phasing, or mapping ambiguity. Unless explicitly guaranteed, sequence changes in the promoter, non-coding exons, and other non-coding regions are not covered by this assay. Please consult the test definition on our website for details regarding regions or types of variants that are covered or excluded for this test. This report reflects the analysis of an extracted genomic DNA sample. In very rare cases, (circulating hematolymphoid neoplasm, bone marrow transplant, recent blood transfusion) the analyzed DNA may not represent the patient's constitutional genome.

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You can customize this test by clicking genes to remove them.

Primary panel

2 genes selected
EXT1
EXT2
Select add-on genes
1 gene

Contiguous deletions of the TRPS1 and EXT1 genes cause Langer-Giedion syndrome, which is characterized by multiple osteochondromas and distinctive facial and skeletal features. In individuals with multiple osteochondromas and additional distinctive facial features such as sparse, slowly growing scalp hair, laterally sparse eyebrows, a bulbous tip of the nose, protruding ears, long flat philtrum and thin upper vermillion border, analysis of the TRPS1 gene may be considered. This gene can be added at no additional charge.

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