The primary cilium is an organelle which plays an important role in the transduction of signals in the Wnt and Sonic hedgehog pathways. Abnormal or absent primary cilia result in various neurodevelopmental, retinal, renal, hepatic and musculoskeletal abnormalities. Joubert syndrome (JS) is a ciliopathy with a prevalence estimated to be between 1:80 000 and 1:100 000. JS occurs due to bi-allelic mutations in one of the 34 identified genes, all of which encode for protein components of the primary cilia. The presentation of JS is highly variable, however a clinical diagnosis can be established by the presence of the molar tooth sign on axial brain MRI, hypotonia in infancy, and developmental delay. JS is less severe than Meckel syndrome (MKS), which is another recessive, and often lethal, ciliopathy. This report outlines an interesting case of JS, in which two novel mutations in B9D1 were identified. This gene is not commonly associated with JS, and is often implicated in MKS. Functional mRNA study was helpful in delineating the pathogenic role of novel variants in this case.

初级纤毛是细胞器，它在Wnt和Sonic刺猬通路的信号转导中起重要作用。原发性纤毛异常或缺失会导致各种神经发育，视网膜，肾脏，肝和肌肉骨骼异常。Joubert综合征（JS）是一种睫状体病，患病率估计在1:80 000和1：100 000之间。JS的发生是由于34个已识别基因之一中的双等位基因突变，所有这些基因都编码该蛋白的蛋白质成分。原发纤毛。JS的表现变化很大，但是可以通过在轴向脑MRI上存在磨牙迹象，婴儿期肌张力低下和发育迟缓来建立临床诊断。JS较Meckel综合征（MKS）严重，后者是另一种隐性且通常是致命的睫状病变。该报告概述了一个有趣的JS案例，鉴定出B9D1。该基因通常不与JS相关，通常与MKS有关。功能性mRNA研究有助于确定这种情况下新变异的致病作用。