To perform a comprehensive characterization of a cohort of patients with congenital mirror movements (CMMs) in Sweden.

Clinical examination with the Woods and Teuber scale for mirror movements (MMs), neuroimaging, navigated transcranial magnetic stimulation (nTMS), and massive parallel sequencing (MPS) were applied.

The cohort is ethnically diverse and includes a total of 7 patients distributed in 2 families and 2 sporadic cases. The degree of MMs was variable in this cohort. MPS revealed 2 novel heterozygous frameshift variants in DCC netrin 1 receptor (DCC). Two siblings harboring the pathogenic variant in c.1466_1476del display a complex syndrome featuring MMs and in 1 case receptive-expressive language disorder, chorea, epilepsy, and agenesis of the corpus callosum. The second DCC variant, c.1729delG, was associated with a typical benign CMM phenotype. No variants in DCC, NTN1, RAD51, or DNAL4 were found for the 2 sporadic CMM cases. However, one of these sporadic cases had concomitant high-risk myelodysplastic syndrome and a homozygous variant in ERCC excision repair like 2 (ERCC6L2). Reorganized corticospinal projection patterns to upper extremities were demonstrated with nTMS.

The presence of chorea expands the clinical spectrum of syndromes associated with variants in DCC. Biallelic pathogenic variants in ERCC6L2 cause bone marrow failure, but a potential association with CMM remains to be studied in larger cohorts.

对瑞典的一组先天性镜子运动 (CMM) 患者进行全面表征。

应用 Woods 和 Teuber 量表进行镜像运动 (MM)、神经影像学、导航经颅磁刺激 (nTMS) 和大规模并行测序 (MPS) 的临床检查。

该队列具有种族多样性，共有 7 名患者，分布在 2 个家庭和 2 例散发病例中。在这个队列中，MM 的程度是可变的。MPS 揭示了 DCC netrin 1 受体 ( DCC ) 中的 2 个新杂合移码变体。携带 c.1466_1476del 致病性变异的两个兄弟姐妹表现出以 MM 为特征的复杂综合征，并在 1 例中出现接受表达性语言障碍、舞蹈症、癫痫和胼胝体发育不全。第二个DCC变体 c.1729delG 与典型的良性 CMM 表型相关。DCC、NTN1、RAD51或DNAL4中没有变体发现 2 例散发性 CMM 病例。然而，其中一个散发病例伴有高危骨髓增生异常综合征和 ERCC 切除修复中的纯合变体，如 2 ( ERCC6L2 )。用 nTMS 展示了重新组织的皮质脊髓投射模式到上肢。

舞蹈病的存在扩大了与DCC变异相关的综合征的临床范围。ERCC6L2中的双等位基因致病变异导致骨髓衰竭，但与 CMM 的潜在关联仍有待在更大的队列中进行研究。