- Patient Preparation
- Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 1 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Characteristics of PTEN hamartoma tumor syndrome (PHTS): Clinical findings are highly variable and include Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome (BRRS), Proteus syndrome (PS) and Proteus-like syndrome (PSL).
CS: Multiple hamartoma syndrome with increased risk for malignant and benign tumors of the breast, thyroid and endometrium. Other associated findings include macrocephaly and mucocutaneous lesions (facial trichilemmomas, palmoplantar keratoses and papillomatous papules).
BRRS: Characterized by macrocephaly, intestinal hamartomatous polyposis, lipomas, hemangiomas and pigmented macules of the glans penis.
PS: A progressive disorder demonstrating mosaic distribution of associated lesions. Findings include hamartomatous tissue overgrowth, hyperostoses, connective tissue and epidermal nevi, dysregulated adipose tissue, vascular malformations and other congenital malformations.
PSL: Describes individuals with significant features of PS who do not meet clinical diagnostic criteria for PS.
Incidence: At least 1 in 200,000 for CS; PS is rare with approximately 120 reported cases; unknown for other PTEN-associated conditions.
Inheritance: Autosomal dominant. All mutations causing PS and 50-90 percent causing CS are de novo.
Penetrance: 99 percent by 30 years of age for CS.
Cause: Pathogenic PTEN gene mutations.
Clinical Sensitivity: Up to 10 percent for BRRS; unknown for CS, PS, and PSL.
Methodology: Multiplex ligation-dependent probe amplification (MLPA) to detect large PTEN coding region deletions/duplications.
Analytical Sensitivity and Specificity of MLPA: 90 and 98 percent, respectively.
Limitations: Diagnostic errors can occur due to rare sequence variations. PTEN single base pair substitutions, small deletions/duplications, regulatory region mutations, deep intronic mutations, and large deletions of exon 3 may not be detected. Deletion/duplication breakpoints will not be determined.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|2002728||PTEN-Related Disorders, Del/Dup|
- Bannayan-Riley-Ruvalcaba Syndrome
- Cowden Syndrome
- Proteus Syndrome
- PTEN deletion/duplication assay