The tumors were sequenced for mutations in the TERT promoter and 22 additional cancer-related genes, interestingly; one patient was shown to carry a deleterious intronic variant in PTEN, a tumor suppressor gene coupled to thyroid tumorigenesis and Cowden syndrome.
We identified one pathogenic variant in PTEN in a patient subsequently confirmed to have a hereditary hamartoma tumor syndrome (Cowden syndrome) and one patient with a pathogenic heterozygous variant in PMS2 that was originally not identified by WES due to low quality reads resulting from pseudogenes.
Here, we conducted a TCA targeted metabolomics study on 511 individuals with CS, CS-like syndrome, or BRRS with various genotypes (PTEN or SDHx, mutant or wild type [WT]) and phenotypes (cancer or ASD) and a series of 187 population controls.
Cowden disease is a genetic disorder associated with a mutation of the PTEN gene and is known to be easily complicated by generalized vascular malformations and malignant tumors.
The diagnosis of Cowden syndrome with PTEN gene mutation, linked to higher risk of neoplasia and occurrence of hamartomatous lesions characteristic of the Lhermitte-Duclos disease (LDD), was confirmed by genetic investigation.
This case highlights the importance of early screening for PTEN mutations in cases of hemimegalencephaly not otherwise explained by another disorder, even in the absence of signs of Proteus syndrome or the full manifestations of Bannayan-Riley Ruvalcaba syndrome.
Sporadic-type intramucosal lipomas were identified in 17 patients (68%) without evidence of Cowden syndrome, including three with normal PTEN genetic testing.
Along with previous reports, this case suggests that acral plexiform PENs may be an early, highly specific finding in CS and highlights the importance of screening these patients for PTEN mutation.
Management of women with breast cancer suspected of CS who test negative for germline PTEN mutations should be managed as per a mutation carrier if she meets CS diagnostic criteria, and should be offered enrollment in research to identify other predisposition genes.
This study reveals the presence of a PTEN Alu insertion hotspot involved in CS, and suggests that undetected PTEN pathogenic variants could contribute to CS.
We studied 34 different germline PTEN intronic variants from 61 CS patients, characterized their PTEN mRNA processing, and analyzed PTEN expression and downstream readouts of P-AKT and P-ERK1/2.
Germline variants in succinate dehydrogenase genes (SDHx) co-occurring with PTEN germline mutations confer a 2-fold increased prevalence (OR 2.7) of thyroid cancer compared to PTEN-associated CS but 50% decreased prevalence (OR 0.54) of thyroid cancer compared to SDHx-associated CS.
When multiple, they are associated with Cowden syndrome (CS), a rare disorder due to an autosomal dominant germline mutation in PTEN (phosphatase and tensin homolog on chromosome 10), a tumor suppressor gene.