Table 1.
Clinical findings in Eurasier dogs with inferior cerebellar hypoplasia resembling a Dandy-Walker-like malformation (DWLM).
Table 2.
Frequencies of the main clinical features in the two patient cohorts.
Table 3.
Neuroimaging findings in Eurasier dogs with familial non-progressive ataxia and inferior cerebellar hypoplasia resembling a DWLM.
Fig 1.
Midsagittal MR brain images (T2-weighted) of the affected Eurasier dogs. In all dogs, a uniform cerebellar malformation was identified, characterized by absence of the caudal portions of the cerebellar vermis and, to a lesser degree, the caudal aspects of the cerebellar hemispheres and large caudal (posterior) fossa fluid accumulations (S2 –S6 Figs.). The fourth ventricle appeared enlarged on midsagittal views and continuous with large retrocerebellar fluid accumulations (large arrow). Tissue remnants in the rostrodorsal caudal fossa correspond to the rostral portions of the cerebellar vermis (small arrow). Note the cyst-like appearance of the fourth ventricle in D. A: dog 6; B: dog 7; C: dog 9; D: dog 10.
Fig 2.
Dorsal MR brain images (T2-weighted) of the affected Eurasier dogs reveal a prominent midline defect with absent caudal portions of the cerebellar vermis (midline) and cerebellar hemispheres (lateral) in association with a large retrocerebellar fluid accumulation. A: dog 6; B: dog 7; C: dog 9; D: dog 10. Images A and D are located more ventrally than B and C.
Fig 3.
Transverse MR brain images (T2-weighted) of four affected Eurasier dogs at the level of the cerebellar peduncles (B) and medulla oblongata (A, C, D). The myelencephalon appears unremarkable. The fourth ventricle has a cyst-like appearance in the rostral sections (B) and is continuous with retrocerebellar cerebrospinal fluid accumulations in the more caudal sections (A, C, D). A: dog 6; B: dog 7; C: dog 9; D: dog 10.
Fig 4.
Computed tomographic images of dog 11, featuring transverse views of the brain at the level of the tympanic bullae, midsagittal and dorsal views. Images show hydrocephalus of the lateral ventricles, supracollicular fluid accumulation (“quadrigeminal cyst”) and large fluid accumulations in the caudal fossa dorsal to the brainstem. The cerebellar remnant tissue in the caudal fossa has a butterfly shape consistent with the loss of midline cerebellar vermis structures. The caudal fossa appears enlarged.
Fig 5.
Midline caudal fossa ratio in Eurasier dogs with (1) and without (2) cerebellar hypoplasia.
Boxplots demonstrate wide variations in midline caudal fossa ratio in Eurasier dogs with inferior cerebellar hypoplasia resembling DWLM (1: range 0.191–0.441; n = 9) compared to Eurasier dogs with unremarkable brain images (2: range 0.2645–0.3300; n = 10). Midline caudal fossa ratio was increased in three dogs with inferior cerebellar hypoplasia resembling DWLM (S1 Table).
Fig 6.
Eurasier dog breed.
Fig 7.
Pedigree of Eurasier dogs with familial non-progressive ataxia and cerebellar hypoplasia resembling a Dandy-Walker like malformation (DWLM). Female dog, ○; male dog, □; black, confirmed cases; the numbers refer to the dog numbers in Tables 1 and 2; gray, suspected cases, based on clinical signs, not confirmed by imaging. All cases could be traced to a common female founder.