Novel KCND3 variant underlying nonprogressive congenital ataxia or SCA19/22 disrupt KV4.3 protein expression and K+ currents with variable effects on channel properties

Ginevra Zanni*, Chen Tsung Hsiao, Ssu Ju Fu, Chih Yung Tang, Alessandro Capuano, Luca Bosco, Federica Graziola, Emanuele Bellacchio, Serenella Servidei, Guido Primiano, Bing Wen Soong, Chung Jiuan Jeng

*此作品的通信作者

研究成果: Article同行評審

3 引文 斯高帕斯(Scopus)

摘要

KCND3 encodes the voltage-gated potassium channel KV4.3 that is highly expressed in the cerebellum, where it regulates dendritic excitability and calcium influx. Loss-of-function KV4.3 mutations have been associated with dominant spinocerebellar ataxia (SCA19/22). By targeted NGS sequencing, we identified two novel KCND3 missense variants of the KV4.3 channel: p.S347W identified in a patient with adult-onset pure cerebellar syndrome and p.W359G detected in a child with congenital nonprogressive ataxia. Neuroimaging showed mild cerebellar atrophy in both patients. We performed a two-electrode voltage-clamp recording of KV4.3 currents in Xenopus oocytes: both the p.G345V (previously reported in a SCA19/22 family) and p.S347W mutants exhibited reduced peak currents by 50%, while no K+ current was detectable for the p.W359G mutant. We assessed the effect of the mutations on channel gating by measuring steady-state voltage-dependent activation and inactivation properties: no significant alterations were detected in p.G345V and p.S347W disease-associated variants, compared to controls. KV4.3 expression studies in HEK293T cells showed 53% (p.G345V), 45% (p.S347W) and 75% (p.W359G) reductions in mutant protein levels compared with the wildtype. The present study broadens the spectrum of the known phenotypes and identifies additional variants for KCND3-related disorders, outlining the importance of SCA gene screening in early-onset and congenital ataxia.

原文English
文章編號4986
期刊International Journal Of Molecular Sciences
22
發行號9
DOIs
出版狀態Published - 1 5月 2021

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