Expanding the Phenotype of Homozygous KCNMA1 Mutations; Dyskinesia, Epilepsy, Intellectual Disability, Cerebellar and Corticospinal Tract Atrophy

Year 2018, Volume: 35 Issue: 4, 336 - 339, 01.07.2018

Gözde Yeşil Ayşe Aralaşmak Enes Akyüz Dilara İçağasıoğlu Türkan Uygur Şahin Yavuz Bayram

Abstract

Background: The KCNMA1 gene encodes the α-subunit of the large
conductance, voltage, and calcium-sensitive potassium channel
(BK channels) that plays a critical role in neuronal excitability.
Heterozygous mutations in KCNMA1 were first illustrated in a large
family with generalized epilepsy and paroxysmal nonkinesigenic
dyskinesia. Recent research has established homozygous KCNMA1
mutations accountable for the phenotype of cerebellar atrophy,
developmental delay, and seizures.
Case Report: Here, we report the case of a patient with a novel
homozygous truncating mutation in KCNMA1 (p.Arg458Ter)
presenting with both the loss- and gain-of-function phenotype with
paroxysmal dyskinesia, epilepsy, intellectual delay, and corticospinal–
cerebellar tract atrophy.
Conclusion: This report extends the KNCMA1 mutation phenotype
with a patient who carries a novel frameshift variant, presenting with
both the gain- and loss-of-function phenotypes along with spinal tract
involvement as a novel characteristic

Keywords

Cerebellar atrophy, dyskinesia, epilepsy, KCNMA1, spinal tract atrophy

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