Scavenger receptor class B, member 2 (SCARB2) is linked to Gaucher disease and Parkinson's disease. Deficiency in the SCARB2 gene causes progressive myoclonus epilepsy (PME), a rare group of inherited neurodegenerative diseases characterized by myoclonus. We found that Scarb2 deficiency in mice leads to age-dependent dietary lipid malabsorption, accompanied with vitamin E deficiency. Our investigation revealed that Scarb2 deficiency is associated with gut dysbiosis and an altered bile acid pool, leading to hyperactivation of FXR in intestine. Hyperactivation of FXR impairs epithelium renewal and lipid absorption. Patients with SCARB2 mutations have a severe reduction in their vitamin E levels and cannot absorb dietary vitamin E. Finally, inhibiting FXR or supplementing vitamin E ameliorates the neuromotor impairment and neuropathy in Scarb2 knockout mice. These data indicate that gastrointestinal dysfunction is associated with SCARB2 deficiency-related neurodegeneration, and SCARB2-associated neurodegeneration can be improved by addressing the nutrition deficits and gastrointestinal issues.
Animals ; Mice ; Dysbiosis/metabolism* ; Mice, Knockout ; Humans ; Lysosomal Membrane Proteins/genetics* ; Receptors, Scavenger/genetics* ; Gastrointestinal Microbiome ; Myoclonic Epilepsies, Progressive/genetics* ; Vitamin E Deficiency/complications* ; Neurodegenerative Diseases/genetics* ; Bile Acids and Salts/metabolism* ; Male ; Lipid Metabolism ; Intestinal Mucosa/pathology*

Anticonvulsants ; therapeutic use ; Clonazepam ; therapeutic use ; Female ; Humans ; Levetiracetam ; therapeutic use ; MERRF Syndrome ; drug therapy ; Male ; Myoclonus ; drug therapy

Adult ; DNA, Mitochondrial ; genetics ; Electroencephalography ; Humans ; MERRF Syndrome ; genetics ; Male ; Mitochondrial Myopathies ; genetics ; Mutation ; RNA, Transfer, Asn ; genetics

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

Patients with dentatorubral-pallidoluysian atrophy occasionally elicit psychosis. So far, one study reported first generation antipsychotics drugs may provide an effective treatment; however, there is no literature on the benefits of second generation antipsychotics. We report on a 44-year-old man with dentatorubral-pallidoluysian atrophy whose psychotic symptoms were effectively treated with olanzapine. Our observation suggests some second generation antipsychotics provide a therapeutic option for ameliorating psychosis in dentatorubral-pallidoluysian atrophy.
Adult ; Antipsychotic Agents ; Humans ; Myoclonic Epilepsies, Progressive* ; Psychotic Disorders* ; Spinocerebellar Degenerations

Unverricht-Lundborg disease (ULD) is a form of progressive myoclonus epilepsy characterized by stimulation-induced myoclonus and seizures. This disease is an autosomal recessive disorder, and the gene CSTB, which encodes cystatin B, a cysteine protease inhibitor, is the only gene known to be associated with ULD. Although the prevalence of ULD is higher in the Baltic region of Europe and the Mediterranean, sporadic cases have occasionally been diagnosed worldwide. The patient described in the current report showed only abnormally enlarged restriction fragments of 62 dodecamer repeats, confirming ULD, that were transmitted from both her father and mother who carried the abnormally enlarged restriction fragment as heterozygotes with normal-sized fragments. We report the first case of a genetically confirmed patient with ULD in Korea.
Blotting, Southern ; Cystatin B ; Cysteine Proteases ; Diagnosis* ; Europe ; Fathers ; Heterozygote ; Humans ; Korea* ; Mothers ; Myoclonic Epilepsies, Progressive ; Myoclonus ; Prevalence ; Seizures ; Unverricht-Lundborg Syndrome*

Adult ; Humans ; Male ; Myoclonic Epilepsies, Progressive ; diagnostic imaging ; genetics ; therapy ; Nerve Tissue Proteins ; genetics ; Pedigree

PURPOSE: Mitochondrial diseases are clinically and genetically heterogeneous disorders, which make their exact diagnosis and classification difficult. The purpose of this study was to identify pathogenic mitochondrial DNA (mtDNA) mutations in 2 Korean families with myoclonic epilepsy with ragged-red fibers (MERRF) and Leigh syndrome, respectively. MATERIALS AND METHODS: Whole mtDNAs were sequenced by the method of mtDNA-targeted next-generation sequencing (NGS). RESULTS: Two causative mtDNA mutations were identified from the NGS data. An m.8344A>G mutation in the tRNA-Lys gene (MT-TK ) was detected in a MERRF patient (family ID: MT132), and an m.9176T>C (p.Leu217Pro) mutation in the mitochondrial ATP6 gene (MT-ATP6) was detected in a Leigh syndrome patient (family ID: MT130). Both mutations, which have been reported several times before in affected individuals, were not found in the control samples. CONCLUSION: This study suggests that mtDNA-targeted NGS will be helpful for the molecular diagnosis of genetically heterogeneous mitochondrial diseases with complex phenotypes.
Classification ; Diagnosis ; DNA, Mitochondrial ; Humans ; Leigh Disease* ; MERRF Syndrome* ; Mitochondrial Diseases ; Phenotype

SCARB2 (scavenger receptor class B, member 2) is a lysosomal membrane glucoprotein, which is encoded by SCARB2 gene. It takes vital parts in the physiological and pathological processes including the transportation of beta-glucocerebrosidase to the lysosome, infection of EV71 and load-induced cardiac myocyte hypertrophy. This article has reviewed the molecular structure and functions of SCARB2 gene and its protein, as well as their relationship with diseases.
Hand, Foot and Mouth Disease ; genetics ; Humans ; Lysosome-Associated Membrane Glycoproteins ; chemistry ; genetics ; physiology ; Myoclonic Epilepsies, Progressive ; genetics ; Parkinson Disease ; genetics ; Receptors, Scavenger ; chemistry ; genetics ; physiology

Quality control for genetic tests has become more important as the test volume and clinical demands increase dramatically. The diagnostic genetics subcommittee of the Korean Association of Quality Assurance for Clinical Laboratories performed two trials for cytogenetics and molecular genetics surveys in 2013. A total of 43 laboratories participated in the cytogenetic surveys, 30 laboratories participated in the fluorescent in situ hybridization surveys, and 122 laboratories participated in the molecular genetics surveys in 2013. Almost all of them showed acceptable results. However, some laboratories had unacceptable results for karyotype nomenclature, detection of complex cytogenetic abnormalities in hematologic neoplasms and constitutional anomalies. The molecular genetics surveys included various tests: Mycobacterium tuberculosis detection, hepatitis B and C virus detection and quantification, human papilloma virus genotyping, gene rearrangement tests for leukaemia and lymphomas, genetic tests for JAK2, fms-related tyrosine kinase 3, Nucleophosmin, cancer-associated genes (KRAS, EGFR and BRAF), hereditary breast and ovarian cancer genes (BRCA1 and BRCA2), Li-Fraumeni syndrome (TP53), Wilson disease (ATP7B), achondroplasia (FGFR3), Huntington disease, spinocerebellar ataxia, spinal and bulbar muscular atrophy, mitochondrial encephalopathy with lactic acidosis and stroke like episodes, myoclonic epilepsy associated with ragged-red fibers, Prader-Willi/Angelman syndrome, Duchenne muscular dystrophy, spinal muscular atrophy, Fragile X syndrome, non-syndromic hearing loss and deafness (GJB2), apolipoprotein E genotyping, methylenetetrahydrofolate reductase genotyping, ABO genotyping and DNA sequence analysis. Molecular genetic surveys showed excellent results for most of the participants. The external quality assessment program for genetic analysis in 2013 was proved to be helpful for continuous education and evaluation of quality improvement.
Achondroplasia ; Acidosis, Lactic ; Apolipoproteins ; Breast ; Chromosome Aberrations ; Cytogenetics ; Deafness ; Education ; Fragile X Syndrome ; Gene Rearrangement ; Genetics* ; Hearing Loss ; Hematologic Neoplasms ; Hepatitis B ; Hepatolenticular Degeneration ; Humans ; Huntington Disease ; In Situ Hybridization, Fluorescence ; Karyotype ; Korea ; Li-Fraumeni Syndrome ; Lymphoma ; MERRF Syndrome ; Methylenetetrahydrofolate Reductase (NADPH2) ; Molecular Biology ; Muscular Atrophy, Spinal ; Muscular Disorders, Atrophic ; Muscular Dystrophy, Duchenne ; Mycobacterium tuberculosis ; Ovarian Neoplasms ; Papilloma ; Protein-Tyrosine Kinases ; Quality Control ; Quality Improvement ; Sequence Analysis, DNA ; Spinocerebellar Ataxias ; Stroke