Figure 1.

Domestic cats with heritable forebrain commissural malformation. Note the abnormal presentation of the pinnae used to determine affection status. (a) Frank—affected sire (left). (b) Camilla—carrier dam. (c) Bobble—affected offspring. These three cats (a–c) were whole genome sequenced. (d) Transverse plane of T2-weighted magnetic resonance imaging of an affected cat at the level of the thalamus. Severe ventriculomegaly, thinning of the cerebral parenchyma and midline structure deficits are seen. A part of the parietal lobe is deficient. (e) Mid-sagittal plane of T2-weighted magnetic resonance imaging of an affected cat (the same cat as (d)). Midline structure deficits are recognized. Note that the spinal cord is formed normally. Interhemispheric cysts are also seen at the rostrotentorial region and the quadrigeminal cistern. Due to the presence of cysts, cerebellar herniation is seen. (f) Gross dorsal view of the dissected head at necropsy. The skin was removed, and the skull was exposed. (g) Transverse sections of formalin-fixed brain tissue at the level of frontal lobe and thalamus. Severe ventriculomegaly, thinning of the cerebral parenchyma and midline structure deficits are seen. Note that a cat whose magnetic resonance imaging of (d) and (e) are presented here is different from cats whose gross pathological pictures of (f) and (g) are provided here.