Data from: Inferior cerebellar hypoplasia resembling a Dandy-Walker-like malformation in purebred Eurasier dogs with familial non-progressive ataxia: a retrospective and prospective clinical cohort study

Cerebellar malformations can be inherited or caused by insults during cerebellar development. To date, only sporadic cases of cerebellar malformations have been reported in dogs, and the genetic background has remained obscure. Therefore, this study`s objective was to describe the clinical characteristics, imaging features and pedigree data of a familial cerebellar hypoplasia in purebred Eurasier dogs. A uniform cerebellar malformation characterized by consistent absence of the caudal portions of the cerebellar vermis and, to a lesser degree, the caudal portions of the cerebellar hemispheres in association with large retrocerebellar fluid accumulations was recognized in 14 closely related Eurasier dogs. Hydrocephalus was an additional feature in some dogs. All dogs displayed non-progressive ataxia, which had already been noted when the dogs were 5 – 6 weeks old. The severity of the ataxia varied between dogs, from mild truncal sway, subtle dysmetric gait, dysequilibrium and pelvic limb ataxia to severe cerebellar ataxia in puppies and episodic falling or rolling. Follow-up examinations in adult dogs showed improvement of the cerebellar ataxia and a still absent menace response. Epileptic seizures occurred in some dogs. The association of partial vermis agenesis with an enlarged fourth ventricle and an enlarged caudal (posterior) fossa resembled a Dandy-Walker-like malformation in some dogs. Pedigree analyses were consistent with autosomal recessive inheritance.

小脑畸形可呈遗传性，亦可由小脑发育过程中的损伤所导致。迄今为止，犬类小脑畸形仅见散发病例报道，其遗传背景仍未明确。因此，本研究旨在描述纯种欧亚犬（Eurasier）家族性小脑发育不全的临床特征、影像学特征及系谱数据。在14只亲缘关系密切的欧亚犬中，观察到一种特征统一的小脑畸形：表现为小脑蚓部尾侧段完全缺失，小脑半球尾侧段亦存在不同程度缺失，同时伴随大量小脑后液体积聚。部分患犬还额外表现出脑积水症状。所有患犬均呈现非进行性共济失调，该症状在患犬5~6周龄时即可被察觉。患犬共济失调的严重程度存在个体差异：轻者仅表现为轻微躯干摇晃、细微辨距不良步态、平衡失调及后肢共济失调；重者可出现幼犬重度小脑共济失调，以及阵发性跌倒或翻滚。对成年患犬的随访检查显示，其小脑共济失调症状有所改善，但威胁反射仍呈缺失状态。部分患犬还出现了癫痫发作症状。部分患犬表现为小脑蚓部部分发育不全，伴第四脑室扩大及颅后窝增大，其影像学特征类似丹迪-沃克样畸形（Dandy-Walker-like malformation）。系谱分析结果符合常染色体隐性遗传模式。