Autism Spectrum of Disorders/Macrocephaly (PTEN)
Collect
Collect whole blood in a purple top (EDTA) tube.
Volume Required
5ml
Minimum Required
3ml
Transport
Refrigerate sample until shipment. Send the sample at room temperature with overnight delivery for receipt Monday through Friday within 24 hours of collection.
Stability
Whole blood can be refrigerated until shipment.
Unacceptable conditions
Heparinized specimens, severely hemolyzed specimens, frozen, clotted or possibly commingled specimens, blood in non-sterile or leaky containers, mislabeled or inappropriately labeled specimens.
Specimen Handling
Do not heat, freeze or centrifuge blood before shipment. Refrigerate sample until shipment.
Days Performed
Mon - Fri 9:00am to 4:00pm
Reported
4-6 weeks
CPT
Seq & Del/Dup: 81321, 81323; Sequence Only- 81321; Del/Dup Only- 81323; Known Point Mutation- 81322
Disease Information
Clinical Features:
Germline mutations in the PTEN gene have been identified in Cowden syndrome, Bannayan-Riley-Ruvalcaba Syndrome, Proteus syndrome and Proteus-like syndrome, now collectively referred to as PTEN Hamartoma Tumor Syndrome (PHTS). Cowden syndrome (CS-MIM 158350) is a multiple hamartoma syndrome with a high risk of breast, thyroid and endometrial cancer. Bannayan-Riley-Ruvalcaba Syndrome (BRRS-MIM 153480) is characterized by macrocephaly, intestinal hamartomatous polyposis, lipomas, and pigmented macules of the glans penis in males. Proteus syndrome (PS-MIM 176920) is a highly variable disorder involving disproportionate overgrowth of multiple tissues, as well as connective tissue nevi, epidermal nevi, and hyperostoses.
Although PTEN is most recognized for its role in carcinogenesis, germline mutations in PTEN have been identified in children with autism and significant macrocephaly with a parent affected with CS or BRRS . Subsequently, additional studies have reported PTEN mutations in children affected with significant macrocephaly and autism.
Molecular Genetics:
The phosphatase and tensin homologue deleted on chromosome 10 (PTEN) gene (MIM 601728) is a tumor suppressor gene located on chromosome 10q23.3. It functions as a dual-specificity phosphatase that is active in numerous pathways involved with cellular growth. Missense, nonsense, splice site mutations, indels and large deletions have been identified in this gene.
Test Methods:
We offer DNA sequence analysis and deletion/duplication testing of the entire coding region of the PTEN gene. These tests can be ordered as a panel or individually. PCR amplification and sequence analysis is performed on the coding exon including splice junctions. The patient’s gene sequence is compared to a reference sequence.
Sequence variants are classified as mutations, variants of unknown significance or benign variants unrelated to disease. Variants of unknown significance may warrant further studies in the patient and other family members. Mutations in promoters, deep intronic regions and other regulatory regions will not be identified with this assay.
Large deletions and duplications will be detected using multiplex ligation-dependent probe amplification assay (MLPA).
Detection Rate:
A number of studies have demonstrated that germline mutations in the PTEN gene are present in 10-20% of individuals with autism spectrum disorders and macrocephaly.
Results:
Test results with interpretation will be mailed and/or faxed to the referring physician or send out lab following completion of the test. Additional reports will be provided as requested.
Utility:
The clinical utility of the assay is to support a clinical diagnosis of the disease, facilitate genetic counseling, and assess the risk to other first degree relatives and to facilitate testing of at - risk family members.
Remarks
Whole blood in EDTA purple top tubes is the preferred sample. High molecular weight genomic DNA, cheek epithelial cells, or other samples containing DNA may be acceptable. Contact the laboratory for specific instructions regarding such samples before sending the sample.
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- (215) 590-8736
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