Confirmation of paternity suggests a new mutation in the factor VII gene: ‘Pater certus quouque est’ ‐ Response to Girolami et al

Thank you for giving us the opportunity to respond to the comments made by Dr Girolami and colleagues concerning our paper describing a patient with severe factor VII deficiency (Hewitt et al, 2005). In our paper, we proposed that the severe deficiency arose from a previously undetected maternal deletion of a region of chromosome 13 (including the factor VII and factor X genes) together with a new paternal point mutation. Dr Girolami and colleagues suggested that (i) germinal mosaicism in the father and (ii) different paternity could also explain the results in our paper. Concerning the paternity, we did state in our paper that paternity was confirmed using the commercially available AmpFlSTR Identifiler polymerase chain reaction Amplification Kit (Applied Biosystems). In addition, this kit was used to verify relationships between all familial samples and rule out any possibility of sample mis-identification. However, Dr Girolami and colleagues are correct in pointing out that we did not give details of the results in our paper. In fact, the short tandem repeat (STR) analysis confirmed paternity by using 16 different STR alleles including the amelogenin allele that distinguishes between the X- and Y-chromosomes. The proband’s family is Caucasian, so using the statistics supplied with the kit (for the US Caucasian population), the STR