J Korean Child Neurol Soc.  2018 Jun;26(2):123-127. 10.26815/jkcns.2018.26.2.123.

CLN6 Mutation in a Patient with Progressive Myoclonus Epilepsy

• Lee HG
• Yoon BA
• Kim YO
• Kim MK
• Woo YJ

• KMID: 2435249
• DOI: http://doi.org/10.26815/jkcns.2018.26.2.123

Abstract

Neuronal ceroid lipofuscinoses (NCLs) are inherited neurodegenerative disorders, which are caused by the accumulation of lipopigment in lysosomes. Variant forms of late infantile NCLs (vLINCLs) characterized by a later onset of seizures and visual impairment (3-8 years) than in the classic form (2-4 years) are caused by mutations of the gene encoding ceroid lipofuscinosis neuronal protein 6 (CLN6). In a girl with progressive myoclonus epilepsy, we found heterozygous variants of CLN6 (NM_017882.2; NP_060352.1): c.296A>G (p.Lys99Arg) and c.307C>T (p.Arg103Trp). They were identified with whole-exome sequencing and verified with Sanger sequencing. At 7 years and 9 months, our patient had developed multiple types of seizures, prominent myoclonus with photosensitivity, regression in motor and language skills, pyramidal and extrapyramidal signs, and brain atrophy in brain images, all of which were progressive and were compatible with vLINCLs. However, this first Korean report shows no visual impairment, which resembles the previously reported Japanese case.

Keyword

Neuronal ceroid-lipofuscinoses; Progressive myoclonus epilepsy; Regression; Child; Whole-exome sequencing

MeSH Terms

Asian Continental Ancestry Group
Atrophy
Brain
Ceroid
Child
Female
Humans
Lysosomes
Myoclonic Epilepsies, Progressive*
Myoclonus
Neurodegenerative Diseases
Neuronal Ceroid-Lipofuscinoses
Neurons
Seizures
Vision Disorders
Ceroid