McMaster University, Department of Neurology, Hamilton, ON, Canada.
McMaster University, Department of Radiology, Hamilton, ON, Canada.
Can J Neurol Sci. 2021 May;48(3):417-418. doi: 10.1017/cjn.2020.195. Epub 2020 Sep 7.
A 56-year-old woman with Down syndrome presented with right-sided weakness and dysarthria, and was found on CT/CTA to have a left middle cerebral artery infarct secondary to moyamoya disease. Her left posterior inferior cerebellar artery (PICA) was fed both by the left vertebral artery, and the left ascending pharyngeal artery (APA), with a variant origin from the internal carotid artery (ICA), then passing through the jugular foramen (Figure 1). Her right PICA originated exclusively from her right occipital artery, also via the jugular foramen (Figure 2). The left vertebral artery originated directly from the aortic arch, whereas the right vertebral artery originated from the brachiocephalic trunk. In addition, she had a trifurcated anterior cerebral artery (ACA), and just prior to this trifurcation, her left ACA was partially supplied by the left ICA, via a superior hypophyseal artery. This case is noteworthy for several reasons. First, though it is exceedingly rare to have the PICA supplied by the jugular branch of the APA, this is the first reported case with an ICA origin of that APA.1,2 The fact that both PICAs in this patient originate from the anterior circulation should remind clinicians that in unexplained posterior circulation infarctions, vascular anatomy should be explored, as carotid-vertebrobasilar anastomoses such as these are rare, but possible. Lastly, the conjunction of moyamoya disease and anomalies of the vertebrobasilar system in a patient with Down syndrome raises interesting questions about the influence of trisomy 21 on the developing vasculature. Connections from the APA to the vertebrobasilar system are hypothesized to result from a lack of regression of an embryological anastomosis, in line with the more common persistent trigeminal and persistent hypoglossal arteries.1 Patients with moyamoya disease have a significantly higher rate of persistent carotid-vertebrobasilar anastomoses than the general population,3 and are also 26 times more likely to have Down syndrome.4 Correspondingly, patients with Down syndrome have significantly higher levels of moyamoya disease, and are more than 10 times as likely as the general population to have abnormalities of the Circle of Willis5 and vertebral arteries.6 Several genes on chromosome 21 are known to affect angiogenesis, namely collagen XIII/endostatin (COL18A1), DYRK1A, and Down syndrome candidate region 1 (DSCR1), possibly through inhibition of VEGF activity.7 Whether additional copies of these genes are responsible for the anomalous vascular development seen in Down syndrome, in turn predisposing to the development of moyamoya disease, could benefit from further exploration.
一位 56 岁的唐氏综合征女性患者出现右侧无力和构音障碍，头部 CT/CTA 检查显示左侧大脑中动脉梗死继发于烟雾病。她的左侧小脑后下动脉（PICA）由左侧椎动脉和左侧咽升动脉（APA）共同供血，起源于颈内动脉（ICA），然后穿过颈静脉孔（图 1）。她的右侧 PICA 仅起源于右侧枕动脉，也通过颈静脉孔（图 2）。左侧椎动脉直接起源于主动脉弓，而右侧椎动脉起源于头臂干。此外，她的大脑前动脉（ACA）呈三叉状，在三叉之前，她的左侧 ACA 部分由颈内动脉通过垂体上动脉供血。该病例有几个原因值得注意。首先，尽管 PICA 由 APA 的颈支供血极为罕见，但这是首例报道的 ICA 起源的 APA 病例。1,2 患者的双侧 PICA 均起源于前循环，这提醒临床医生，在不明原因的后循环梗死中，应探查血管解剖结构，因为这种颈动脉-椎基底动脉吻合极为罕见，但也有可能存在。最后，唐氏综合征患者合并烟雾病和椎基底动脉系统异常，这引发了关于 21 三体对发育中血管的影响的有趣问题。APA 与椎基底系统的连接被假设是由于胚胎吻合的缺乏而导致的，这与更常见的永存三叉动脉和永存舌下动脉一致。1 烟雾病患者的颈内-椎基底吻合的发生率明显高于普通人群，3 并且患唐氏综合征的风险也高出 26 倍。4 相应地，唐氏综合征患者烟雾病的发病率显著升高，其 Willis 环和椎动脉异常的发生率是普通人群的 10 倍以上。5,6 21 号染色体上有几个基因已知会影响血管生成，即胶原 XIII/内皮抑素（COL18A1）、双特异性酪氨酸磷酸化调节激酶 1A（DYRK1A）和唐氏综合征候选区 1（DSCR1），可能通过抑制 VEGF 活性。7 这些基因的额外拷贝是否导致唐氏综合征患者的异常血管发育，从而易患烟雾病，这需要进一步探讨。
