Whilst the small number of children with seronegative AIH precludes any meaningful statistical analysis, the data is in line with the data from adults [19] and is reassuring that there might be additional value for the quantification of pIgG in seronegative AIH, especially as pIgG levels did not differ dependent on the presence or absence of ANA or anti-SMA. This evidence concerns the gene BTG3 and autoimmune hepatitis.