A PTEN mutation, c.1003C>Tp.(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.
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.