Abstract：
LAMB2 gene disorders present with different phenotypes. Pierson syndrome (PS) is a common phenotype associated with LAMB2 variants. Neuromuscular phenotype has been reported including hypotonia and developmental delay. However, neuromuscular junction abnormalities represented as congenital myasthenic syndrome (CMS) was reported in one adult patient only. Here, in this paper, we present two pediatric cases with a severe presentation of PS and have CMS so expanding the knowledge of LAMB2 related phenotypes. The first patient had hypotonia and global developmental delay. Targeted genetic testing panel demonstrated homozygous pathogenic variant in the LAMB2 gene (c.5182C>T, pGln1728*) which was reported by Maselli et al. 2009. Repetitive nerve stimulation (RNS) showed a decremental response at low frequency of 3 Hz. On the other hand, the second patient had profound weakness since birth. Tri-Whole exome sequencing showed homozygous pathogenic variant in the LAMB2 gene c.2890C>T, pArg964*. A trial of salbutamol did not improve the symptoms. Both patients passed away from sequala of PS. The spectrum of phenotypic changes associated with LAMB2 mutations is still expanding, and further investigation into the various clinical and morphologic presentations associated with these mutations is important to better identify and manage affected individuals.
摘要：
LAMB2基因紊乱表现为不同的表型。Pierson综合征(PS)是与LAMB2变体相关的常见表型。据报道，神经肌肉表型包括张力减退和发育迟缓。然而,仅在一名成年患者中报告了以先天性肌无力综合征（CMS）为代表的神经肌肉接头异常。这里,在本文中，我们介绍了2例出现严重PS和CMS的儿科病例,从而扩大了对LAMB2相关表型的认识.首例患者有张力减退和整体发育迟缓。靶向遗传检测小组证明了LAMB2基因中的纯合致病性变异（c.5182C>T，pGln1728*)，由Maselli等人报道。2009.重复神经刺激（RNS）在3Hz的低频率下显示出减弱的反应。另一方面,第二位患者自出生以来就有严重的弱点。三全外显子组测序显示LAMB2基因c.2890C>T纯合致病变异，pArg964*。沙丁胺醇的试验没有改善症状。两名患者均因PS后遗症去世。与LAMB2突变相关的表型变化谱仍在扩大，进一步研究与这些突变相关的各种临床和形态学表现对于更好地识别和管理受影响的个体非常重要.
