The porcine congenital splay leg syndrome (PCS), even though being of transient nature, is still one of the most important causes for piglet losses due to its high incidence and mortality. Although, described decades ago, the pathogenetic mechanism is still elusive. Numerous, mostly descriptive studies characterized the syndrome at clinical, histological and cellular levels but resulted in a highly diverse picture of the syndrome. Broad variability in phenotypical expression and, in case of proper care, the rapid recovery of affected animals complicated a systematical analysis of the underlying pathogenesis. Although, several environmental factors were discussed as potential causes of PCS, most of the evidence points to a hereditary basis of PCS. Nevertheless, only few of the suggested candidate genes from transcriptome and mapping analyses, like F-box protein 32 (FBXO32), could be confirmed so far. Only recently, a genome wide association study revealed genomic regions on five porcine chromosomes and named a number of potential candidate genes, among them homer scaffold protein 1 (HOMER1). This new candidate—a cellular scaffold protein—plays a role in a plethora of cellular signaling cascades, and is not only involved in skeletal muscle differentiation but also critical for muscular function. In this review, we critically elucidate the current state of knowledge in the field and evaluate current achievements in the identification of the pathogenetic mechanism for the syndrome.

猪先天性八字腿综合征（PCS）虽然是暂时性的，但由于其高发病率和死亡率，仍然是仔猪损失的最重要原因之一。尽管几十年前已有描述，其发病机制仍然难以捉摸。许多主要是描述性的研究在临床、组织学和细胞水平上描述了该综合征的特征，但得出了该综合征的高度多样化的图像。表型表达的广泛变异性以及在适当护理的情况下，受影响动物的快速恢复使对潜在发病机制的系统分析变得复杂。尽管一些环境因素被认为是 PCS 的潜在原因，但大多数证据都表明 PCS 具有遗传基础。然而，到目前为止，只有少数来自转录组和作图分析的建议候选基因得到证实，例如 F-box 蛋白 32 (FBXO32)。就在最近，一项全基因组关联研究揭示了猪的 5 条染色体上的基因组区域，并命名了许多潜在的候选基因，其中包括荷马支架蛋白 1 (HOMER1)。这种新的候选物——一种细胞支架蛋白——在大量的细胞信号级联中发挥作用，不仅参与骨骼肌分化，而且对肌肉功能也至关重要。在这篇综述中，我们批判性地阐明了该领域的当前知识状况，并评估了当前在识别该综合征发病机制方面取得的成就。