Ramón-Gómez J L, Bernal-Pacheco O, Zarante-Bahamón A M, Martínez-Córdoba N, Lince-Rivera I
Instituto Roosevelt, Bogotá DC, Colombia.
Hospital Universitario San Ignacio, Bogotá DC, Colombia.
Rev Neurol. 2024 May 16;78(10):285-291. doi: 10.33588/rn.7810.2023279.
KMT2B-related dystonia is a childhood-onset movement disorder characterized by focal dystonia of the lower extremities progressing to generalized dystonia with predominant cervical, cranial, and laryngeal involvement. So far, fewer than 100 variants have been reported, the vast majority being de novo mutations. The presenting frame of KMT2B dystonia, with dysmorphology features and other complex neurologic symptoms shows the spectrum of KMT2B dystonia as a probable syndromic disease, rather than an isolated early-onset dystonia, which has been the classic view of the condition.
We report three patients who presented regression in their neurodevelopment, focal dystonia of the lower limbs with subsequent generalization, in whom two de novo variants were reported in the KMT2B gene, with a mean age of presentation lower than the average reported worldwide.
We describe the largest local series of patients with KMT2B dystonia in Colombia (to our knowledge), which allows us to expand the genotype-phenotype relationship of this genetic dystonia. Although many affected individuals follow a similar disease course, it is important to determine clinical features that may be associated such as neurodevelopmental regression.
KMT2B相关肌张力障碍是一种儿童期起病的运动障碍，其特征为下肢局灶性肌张力障碍进展为全身性肌张力障碍，主要累及颈部、头部和喉部。到目前为止，报道的变异少于100种，绝大多数为新发突变。KMT2B肌张力障碍的表现形式，伴有畸形特征和其他复杂的神经症状，表明KMT2B肌张力障碍可能是一种综合征性疾病，而非孤立的早发性肌张力障碍，而后者一直是对该病的经典看法。
我们报告了3例患者，他们出现神经发育倒退、下肢局灶性肌张力障碍并随后泛化，其中2例在KMT2B基因中报告了新发变异，其平均发病年龄低于全球报告的平均水平。
我们描述了哥伦比亚（据我们所知）最大的KMT2B肌张力障碍患者本地系列，这使我们能够扩展这种遗传性肌张力障碍的基因型-表型关系。尽管许多受影响个体遵循相似的病程，但确定可能相关的临床特征（如神经发育倒退）很重要。
