This test analyzes the PTEN gene, which is associated with PTEN hamartoma tumor syndrome (PHTS) as well as PTEN-related autism spectrum disorder.
PTEN hamartoma tumor syndrome (PHTS) includes the clinical subtypes of Cowden syndrome, Bannayan-Riley-Ruvalcaba syndrome, PTEN-related Proteus syndrome, and Proteus-like syndrome. Characteristics of these syndromes include hamartomas, macrocephaly, intellectual disability, and cancers of the breast, thyroid, and uterus. In addition, pathogenic variants in PTEN are associated with autism spectrum disorder and have been observed in individuals without any PHTS phenotype.
Genetic testing of this gene 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.
PTEN can also be ordered as part of a larger panel to test for different types of hereditary cancer conditions. Depending on the individual’s clinical and family history, one of these larger panels may be appropriate. Any of these larger panels can be ordered at no additional charge.
PTEN hamartoma tumor syndrome (PHTS) encompasses four, clinically distinct, allelic disorders characterized by the formation of hamartomatous tumors. Hamartomas are caused by unregulated cellular proliferation, leading to a high risk of benign and malignant tumors requiring cancer surveillance of the thyroid, skin, breast, endometrium, kidney and colon. Individuals with Cowden syndrome have a lifetime risk of developing breast cancer up to 85% with 50% penetrance by age 50. Approximate lifetime risks for other cancers include 35% risk of thyroid cancer (typically follicular), 28% risk of endometrial cancer, 9% risk of colorectal cancer, and 35% risk of renal cell carcinoma.
Bannayan-Riley-Ruvalcaba syndrome confers similar cancer risks as Cowden syndrome; however, BRRS is a congenital disorder characterized by macrocephaly and lipomas.
PTEN-related Proteus/Proteus-like syndromes are overgrowth syndromes characterized by childhood onset progressive overgrowth of the skin, skeleton, central nervous system and adipose tissues.
In addition, pathogenic variants in PTEN have been associated with autism spectrum disorder, with and without macrocephaly, in the absence of a family history of PHTS. More frequent white matter abnormalities and more significant cognitive delays have been reported in individuals with PTEN-related autism spectrum disorder versus non-PTEN-related autism spectrum disorder.
More than 90% of individuals with Cowden syndrome will manifest clinical features by their late twenties. By age 30, 99% will develop characteristic skin and mucous membrane findings. However, affected individuals can present with varying clinical features, even among members of the same family. Because we cannot predict which cancers may develop, additional medical management strategies focused on cancer prevention and early detection may benefit most patients who are found to have a pathogenic variant.
Individuals with PTEN mutations have an increased risk of developing the following cancers:
Breast cancer in men with germline PTEN mutations has been reported, but the exact risk is unknown. Central nervous syndrome cancers have been reported, but are thought to be rare.
The clinical sensitivity of this test is dependent on the patient’s clinical presentation. For each clinical subtype, the chart below shows the percentage of clinical cases in which a pathogenic variant is expected to be identified through analysis of the PTEN gene.
|Clinical subtype||% of clinical cases with a pathogenic variant in PTEN|
|Cowden syndrome (CS)||85%|
|Bannayan-Riley-Ruvalcaba syndrome (BRRS)||70%|
|PTEN-related Proteus/Proteus-Like Syndrome||20-50%|
|PTEN-related macrocephalic autism spectrum disorder||10%|
PHTS and PTEN-related autism spectrum disorder are inherited in an autosomal dominant pattern.
The prevalence of PHTS is currently unknown.
PTEN analysis may be considered in individuals with:
Clinical diagnostic criteria have been established:
Testing may also be considered for those who do not meet the strict clinical diagnostic criteria for Cowden but have a strong clinical suspicion of having the condition.
For management recommendations, please refer to:
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 in the transcript listed below. In addition, analysis covers the select non-coding variants specifically defined in the table below. Any variants that fall outside these regions are not analyzed. Any specific limitations in the analysis of these genes are also listed in the table below.
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.
|Gene||Transcript reference||Sequencing analysis||Deletion/Duplication analysis|
PTEN: Deletion/duplication analysis covers the promoter region.