Developmental progression of the Spider Lamb Syndrome

Abstract

The progression of ovine hereditary chondrodysplasia, referred to as the Spider Lamb Syndrome (SLS), was characterized by collecting fetuses at the end of the second trimester, the middle of the third trimester, and the end of gestation. The SLS fetuses were produced by artificially inseminating three affected SLS ewes with frozen semen collected from an affected SLS ram, and surgically transferring the resulting embryos to unaffected recipient ewes. All resultant offspring possessed morphologic abnormalities consistent with a clinical diagnosis of SLS, although the degree of symptoms of the syndrome varied from animal to animal. The variable SLS clinical involvement was not correlated with the degree of symptoms expressed by the parents. We have confirmed an autosomal recessive mode of inheritance with complete penetrance and variable expressivity of the SLS phenotype with developmental expression of gross pathological changes apparent by the completion of the second gestational trimester.