NRXN-1 not likely to have anything to do with paternal age

The neurexin deletions in the two sisters are not point mutations. Point mutations affect only a single nucleotide or just a few nucleotides. The deletion in these neurexin cases involved 450,000 nucleotides.


It is very unlikely that two new mutations of the same gene in two different children (except identical twins) would occur under any circumstances. These cases probably represent gonadal mosaicism in one of the parents (assuming both were tested and neither carries the same deletion).

Moreover, I know of no evidence that deletions of the type that apparently occurred in these girls have anything to do with the age of either parent.