ISSN : 2146-3123
E-ISSN : 2146-3131

Expanding the Phenotype of Homozygous KCNMA1 Mutations; Dyskinesia, Epilepsy, Intellectual Disability, Cerebellar and Corticospinal Tract Atrophy
Gözde Yeşil1, Ayşe Aralaşmak2, Enes Akyüz1, Dilara İçağasıoğlu3, Türkan Uygur Şahin4, Yavuz Bayram5
1Department of Medical Genetics, Bezmialem Vakıf University School of Medicine, İstanbul, Turkey
2Department of Radiology, Bezmialem Vakıf University School of Medicine, İstanbul, Turkey
3Department of Child Disease and Health, Bezmialem Vakıf University School of Medicine, İstanbul, Turkey
4Department of Child Neurology, Bezmialem Vakıf University School of Medicine, İstanbul, Turkey
5Mol. & Human Gen/Lupski Lab, Baylor College of Medicine, Texas, USA
DOI : 10.4274/balkanmedj.2017.0986

Background: The KCNMA1 gene encodes the α-subunit of the large conductance, voltage and calcium-sensitive potassium channel (BK channels) which plays an important role in neuronal excitability. Heterozygous mutations in KCNMA1 were firstly described in a large family with generalized epilepsy and paroxysmal nonkinesigenic dyskinesia. Recently, homozygous KCNMA1 mutations were reported to cause a phenotype of cerebellar atrophy, developmental delay and seizures.
Case Report: Herein; we report a patient with a novel homozygous truncating mutation in KCNMA1 (p.Arg458Ter) presenting both loss and gain of function phenotype with paroxysmal dyskinesia, epilepsy, intellectual delay plus corticospinal-cerebellar tract atrophy.
Conclusion: We expand the KNCMA1 mutation phenotype with a patient who carries a novel frameshift variant, presenting with both gain and loss of function phenotypes and also spinal tract involvement as novel feature.

Keywords : KCNMA1, epilepsy, dyskinesia, cerebellar atrophy, spinal tract atrophy

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