A novel missense creatine mutant of CaBP4, c.464G>A (p.G155D), associated with autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), reduces the expression of CaBP4

Yuxiong Guo; Qinfei Miao; Yuxin Zhang; Chun Wang; Mingjuan Liang; Xueping Li; Weifeng Qiu; Gangan Shi; Qiongxiang Zhai; Zhihong Chen

doi:10.21037/tp-22-54

A novel missense creatine mutant of CaBP4, c.464G>A (p.G155D), associated with autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), reduces the expression of CaBP4

Transl Pediatr. 2022 Mar;11(3):396-402. doi: 10.21037/tp-22-54.

Authors

Yuxiong Guo^#^{1

2}, Qinfei Miao^#³, Yuxin Zhang¹, Chun Wang¹, Mingjuan Liang^{1

2}, Xueping Li^{1

4}, Weifeng Qiu^{1

4}, Gangan Shi^{1

5}, Qiongxiang Zhai^{1

2}, Zhihong Chen^{1

2}

Affiliations

¹ Department of Pediatrics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangdong Academy of Neuroscience, Guangzhou, China.
² Second School of Clinical Medicine, Southern Medical University, Guangzhou, China.
³ Department of Neurology Rehabilitation, Guangdong Maternal and Child Hospital, Guangzhou, China.
⁴ Shantou University, Shantou, China.
⁵ South China University of Technology, Guangzhou, China.

^# Contributed equally.

Abstract

Background: CaBP4 encodes Ca²⁺-binding protein 4, a neuronal Ca²⁺-binding protein that participates in many cellular processes by regulating the concentration of free Ca²⁺ ions. De novo CaBP4 variants have been identified as a cause of congenital stationary night blindness (CSNB). However, we recently reported a 4-generation pedigree with 11 individuals diagnosed with autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) that were validated with only one novel missense mutation, c.464G>A (p.G155D), in CaBP4. De novo CaBP4 variants have never been reported to be related with ADNFLE. This study aimed to identify whether c.464G>A (p.G155D) in CaBP4 reduced the expression of CaBP4.

Methods: In vitro experiments using recombinant protein expressed in human neuron cells were utilized in this study. Real-time polymerase chain reaction (RT-PCR) was performed to evaluate the effect of c.464G>A on CaBP4 mRNA expression. Western blot was performed to assess the effect of c.464G>A on CaBP4 protein expression.

Results: According to the RT-PCR and Western blot results, c.464G>A (p.G155D) was associated with an increased expression of CaBP4 mRNA and a reduced expression of CaBP4 protein.

Conclusions: These results reveal that c.464G>A (p.G155D) in CaBP4 reduced the expression of CaBP4 by reducing the stability of the CaBP4 protein. Mutations in the CaBP4 gene may be associated with ADNFLE.

Keywords: Ca2+-binding protein 4 (CaBP4); Western blot; autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE); epilepsy; real-time polymerase chain reaction (RT-PCR).