Potter K A, Weston J F, Munday J S, Johnstone A C
Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North 4442, New Zealand.
N Z Vet J. 2010 Dec;58(6):315-8. doi: 10.1080/00480169.2010.69763.
In 2008, six lambs within a flock of Dorper-cross sheep were born with musculoskeletal and neurological disease. Clinical signs included hindlimb weakness, and urinary incontinence.
All lambs had focal, inverted areas of alopecic skin over the caudal sacrum, and short, often kinked tails. Four affected lambs were subject to euthanasia, and necropsied. On gross examination, the arches of sacral vertebrae were absent, and spinal nerves and meninges were adherent to the overlying subcutis. Other gross lesions included narrow, elongated skulls, herniation of the occipital lobes into the caudal fossas, hydrocephalus, and syringomyelia. One lamb had coning of the cerebellar vermis, but cerebellar herniation through the foramen magnum was not identified.
Spina bifida, with associated malformations of the central nervous system.
Examination of breeding records suggested either an autosomal recessive or partially penetrant autosomal dominant pattern of inheritance. Because of the associated tail lesions it is proposed that the pathogenesis of this syndrome involves a defect in development of the tail bud (secondary neurulation), that tethering of the spinal cord resulted in the clinical signs, and abnormal pressure of the cerebral spinal fluid resulted in the defects in the skull and brain.
2008年，一群杜泊杂交绵羊中有6只羔羊出生时患有肌肉骨骼和神经系统疾病。临床症状包括后肢无力和尿失禁。
所有羔羊尾骶部均有局部脱毛的倒三角区域，尾巴短且常呈扭结状。4只患病羔羊实施了安乐死并进行了尸检。大体检查发现，骶椎弓缺失，脊神经和脑膜与上方皮下组织粘连。其他大体病变包括颅骨狭窄细长、枕叶疝入枕骨大孔、脑积水和脊髓空洞症。1只羔羊有小脑蚓部下疝，但未发现小脑通过枕骨大孔疝出。
脊柱裂，伴有中枢神经系统相关畸形。
对繁殖记录的检查提示为常染色体隐性或部分显性的常染色体显性遗传模式。由于伴有尾部病变，推测该综合征的发病机制涉及尾芽（继发性神经管形成）发育缺陷，脊髓受牵拉导致临床症状，脑脊液压力异常导致颅骨和脑部缺陷。
