BACKGROUND Balanced structural variants are mostly described in disease with gene disruption or subtle rearrangement at breakpoints. CASE PRESENTATION Here we report a patient with mild intellectual deficiency who carries a de novo balanced translocation t(3;5). Breakpoints were fully explored by microarray, Array Painting and Sanger sequencing. No gene disruption was found but the chromosome 5 breakpoint was localized 228-kb upstream of the MEF2C gene. The predicted Topologically Associated Domains analysis shows that it contains only the MEF2C gene and a long non-coding RNA LINC01226. RNA studies looking for MEF2C gene expression revealed an overexpression of MEF2C in the lymphoblastoid cell line of the patient. CONCLUSIONS Pathogenicity of MEF2C overexpression is still unclear as only four patients with mild intellectual deficiency carrying 5q14.3 microduplications containing MEF2C are described in the literature. The microduplications in these individuals also contain other genes expressed in the brain. The patient presented the same phenotype as 5q14.3 microduplication patients. We report the first case of a balanced translocation leading to an overexpression of MEF2C similar to a functional duplication.

中文翻译：

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染色质组织的破坏导致智力障碍中的MEF2C基因过表达：一例病例报告。

背景技术平衡的结构变体主要在疾病中描述为在断裂点处具有基因破坏或微妙的重排。病例介绍在这里，我们报告了一名轻度智力缺陷患者，该患者进行了从头平衡转位t（3; 5）。通过微阵列，Array Painting和Sanger测序充分探索了断点。没有发现基因破坏，但是5号染色体的断点位于MEF2C基因上游228kb。预测的拓扑相关域分析显示，它仅包含MEF2C基因和一个长的非编码RNA LINC01226。寻找MEF2C基因表达的RNA研究表明，该患者的淋巴母细胞系中MEF2C过表达。结论MEF2C过表达的致病性仍不清楚，因为文献中仅描述了4名携带5q14.3微复制的轻度智力缺陷患者。这些个体中的微复制也包含在大脑中表达的其他基因。该患者的表型与5q14.3微复制患者相同。我们报告的平衡移位导致MEF2C过度表达类似于功能重复的首例。