A PTEN mutation, c.1003C>T p.(Arg335Ter), was subsequently identified as the cause of Cowden syndrome in another family member (a nephew) with dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease), and genetic testing in the proband's daughter indicated that he was an obligate carrier of the mutation.
We have identified a germline mutation, R335X, in PTEN in a family consisting of two female members with the phenotypic findings of CS and two male members with the phenotypic findings of BZS.
While all the mutations we identified are novel in BZS, 1003C-->T (nonsense mutation) and 209+5G-->A (putative splice site mutation) have been previously reported in unrelated families with CS and Lhermitte Duclos disease.