Ventricular dilatation after intraventricular haemorrhage (IVH) has been revealed to result from the widespread deposition of ECM proteins in the subarachnoid space, which can be degraded by MMP‐9, implying that MMP‐9 possibly functions in the resolution of progressive ventricular dilation post‐IVH (Okamoto et al., 2010). The gene discussed is MMP9; the disease is Vascular dilatation.