Importantly, because the C57BL/6N strain arose from C57BL/6J (Simon et al., 2013), these two substrains are much more genetically closer than B6 and 129, implying that a comparative dissection of the genetic modifier(s) of hydrocephalus development due to loss of Ccdc151 function could be substantially facilitated by fewer genetic variations between C57BL/6N and C57BL/6J substrains. This evidence concerns the gene ODAD3 and Hydrocephalus.