Invitae Congenital Amegakaryocytic Thrombocytopenia Test


Test description

This test analyzes the MPL gene, which is associated with congenital amegakaryocytic thrombocytopenia (CAMT). CAMT is an infantile onset condition that is characterized by bone marrow failure and low numbers of megakaryocytes and platelets. Certain variants cause CAMTII, which is a milder form of disease.

Genetic testing of these genes may confirm a diagnosis and help guide treatment and management decisions. Identification of a disease-causing variant would also guide testing and diagnosis of at-risk relatives. This test is specifically designed for heritable germline mutations and is not appropriate for the detection of somatic mutations in tumor tissue.

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Primary panel (1 gene)


Alternative tests to consider

These genes can also be ordered as part of a broader panel. Depending on the individual’s clinical and family history, this panel may be appropriate and can be ordered at no additional charge.

Congenital amegakaryocytic thrombocytopenia (CAMT)

Congenital amegakaryocytic thrombocytopenia (CAMT) is characterized by low platelet count (thrombocytopenia), absent or low numbers of megakaryocytes (megakaryocytopenia) and bone marrow failure. CAMT typically presents with a bleeding episode in early infancy. Individuals are at risk for aplastic anemia and leukemia.

A milder presentation of CAMT, known as CAMT II, is characterized by increasing platelet counts that approach near-normal in the first year of life and an onset of bone marrow failure after the age of 3.

Pathogenic MPL variants have also been shown to segregate with autosomal dominant hereditary thrombocythemia. but they are unlikely to be a common cause of thrombocythemia.

The majority of cases of congenital amegakaryocytic thrombocytopenia can be attributed to pathogenic variants identified in MPL.

CAMT is inherited in an autosomal recessive manner.

CAMT is thought to be rare and its exact prevalence is unknown.

MPL testing may be considered in patients with an onset of severe pancytopenia, decreased bone marrow activity, and very low platelet counts at birth or in childhood.

Assay and technical 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, +/- 10 base pairs of adjacent intronic sequence, and select noncoding variants. Our assay provides a Q30 quality-adjusted mean coverage depth of 350x (50x minimum, or supplemented with additional analysis). Variants classified as pathogenic or likely pathogenic are confirmed with orthogonal methods, except individual variants that have high quality scores and previously validated in at least ten unrelated samples.

Our analysis detects most intragenic deletions and duplications at single exon resolution. However, in rare situations, single-exon copy number events may not be analyzed due to inherent sequence properties or isolated reduction in data quality. If you are requesting the detection of a specific single-exon copy number variation, please contact Client Services before placing your order.

Gene Transcript reference Sequencing analysis Deletion/Duplication analysis
MPL NM_005373.2