title: A homozygous mutation in KCTD7 links neuronal ceroid lipofuscinosis to the ubiquitin-proteasome system.
abstract: Neuronal ceroid lipofuscinosis (NCL) is a genetically heterogeneous group of lysosomal diseases that collectively compose the most common Mendelian form of childhood-onset neurodegeneration. It is estimated that ∼8% of individuals diagnosed with NCL by conservative clinical and histopathologic criteria have been ruled out for mutations in the nine known NCL-associated genes, suggesting that additional genes remain unidentified. To further understand the genetic underpinnings of the NCLs, we performed whole-exome sequencing on DNA samples from a Mexican family affected by a molecularly undefined form of NCL characterized by infantile-onset progressive myoclonic epilepsy (PME), vision loss, cognitive and motor regression, premature death, and prominent NCL-type storage material. Using a recessive model to filter the identified variants, we found a single homozygous variant, c.550C>T in KCTD7, that causes a p.Arg184Cys missense change in potassium channel tetramerization domain-containing protein 7 (KCTD7) in the affected individuals. The mutation was predicted to be deleterious and was absent in over 6,000 controls. The identified variant altered the localization pattern of KCTD7 and abrogated interaction with cullin-3, a ubiquitin-ligase component and known KCTD7 interactor. Intriguingly, murine cerebellar cells derived from a juvenile NCL model (CLN3) showed enrichment of endogenous KCTD7. Whereas KCTD7 mutations have previously been linked to PME without lysosomal storage, this study clearly demonstrates that KCTD7 mutations also cause a rare, infantile-onset NCL subtype designated as CLN14.
authors: Center for Human Genetic Research, Massachusetts General Hospital, Boston, 02114, USA.
authors: John F
authors: JF
authors: Staropoli
authors: Amel
authors: A
authors: Karaa
authors: Elaine T
authors: ET
authors: Lim
authors: Andrew
authors: A
authors: Kirby
authors: Naser
authors: N
authors: Elbalalesy
authors: Stephen G
authors: SG
authors: Romansky
authors: Karen B
authors: KB
authors: Leydiker
authors: Scott H
authors: SH
authors: Coppel
authors: Rosemary
authors: R
authors: Barone
authors: Winnie
authors: W
authors: Xin
authors: Marcy E
authors: ME
authors: MacDonald
authors: Jose E
authors: JE
authors: Abdenur
authors: Mark J
authors: MJ
authors: Daly
authors: Katherine B
authors: KB
authors: Sims
authors: Susan L
authors: SL
authors: Cotman
mesh_terms: D000818:Animals; D002675:Child, Preschool; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D007223:Infant; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009154:Mutation; D009472:Neuronal Ceroid-Lipofuscinoses / Q000235:genetics*; D010375:Pedigree; D015221:Potassium Channels / Q000235:genetics*; D046988:Proteasome Endopeptidase Complex / Q000235:genetics; D025801:Ubiquitin / Q000235:genetics
chemical_list: C522280:KCTD7 protein, human; D015221:Potassium Channels; D025801:Ubiquitin; D046988:Proteasome Endopeptidase Complex