RNASEH2A and Aicardi-Goutieres syndrome: To determine the cellular effect of RNase H2 disease mutations, we complemented RNASEH2A‐KO cells with RNASEH2A‐G37S and RNASEH2A‐E225G, the only two missense mutations that have been found so far as causative homozygous changes in the catalytic subunit in AGS patients (Rice et al, 2013).