(a) Familial pedigree and PNKP (red) and PCDH15 (blue) mutations. WT, wild-type allele. (b) Brain magnetic resonance imaging (MRI) of the patient at 16 days after birth (T2 weighted images). Microcephaly, a simplified gyral pattern with normal cortical thickness, slightly enlarged ventricles, cerebellar hypoplasia, and proportional reduction of white matter volume with a thin corpus callosum are evident. (c) Schematic presentation of PNKP protein and location of mutations. Five reported mutations are depicted above the PNKP protein. Two novel mutations (A55S and G292R) found in this study are shown below the protein. Three boxes indicate functional domains. A full color version of this figure is available at the Journal of Human Genetics journal online.