Ho Kwo Wei David, Jerath Nivedita U
University of Florida, Department of Neurology, USA.
Case Rep Genet. 2018 Dec 25;2018:2618071. doi: 10.1155/2018/2618071. eCollection 2018.
The clinical effect of T118M variant of the PMP22 gene has been controversial. Several studies have suggested that it may be autosomal recessive, partial loss of function, or a benign variant. Here we report three cases in further support that the T118M variant of the PMP22 gene is a partial loss of function variant. These three unrelated cases were heterozygotes with the T118M variant of the PMP22 gene. All three cases presented with painful peripheral neuropathy and varying degrees of Charcot-Marie-Tooth exam features. Electrophysiological studies revealed polyneuropathy with axonal and demyelinating features in one case, but there were minimal electrophysiological changes in the other two cases. We propose that the T118M variant can cause painful peripheral neuropathy, which may be an underrecognized feature of this variant.
PMP22基因T118M变异体的临床效应一直存在争议。多项研究表明，它可能是常染色体隐性、功能部分丧失或良性变异。在此，我们报告三例病例，进一步支持PMP22基因的T118M变异体是功能部分丧失变异体这一观点。这三例无关病例均为携带PMP22基因T118M变异体的杂合子。所有三例病例均表现为疼痛性周围神经病变以及不同程度的夏科-马里-图斯（Charcot-Marie-Tooth）检查特征。电生理研究显示，其中一例存在轴索性和脱髓鞘性特征的多发性神经病变，但另外两例的电生理变化极小。我们认为，T118M变异体可导致疼痛性周围神经病变，这可能是该变异体一个未被充分认识的特征。
