title: C9orf72 expansion as a possible genetic cause of Huntington disease phenocopy syndrome.
abstract: Huntington disease (HD), the most common inherited cause of chorea, is an autosomal dominant disorder, caused by an expanded trinucleotide CAG repeat (>39) in the HTT gene on chromosome 4p16.3. Among patients diagnosed as HD solely on clinical grounds, a certain number was negative on genetic testing for HD. Therefore, HD-like disorders comprised a number of genetic causes of chorea, that may be indistinguishable from HD (e.g. HD phenocopy syndrome). Recent data suggested that the C9orf72 expansion may be the most common genetic cause of HD phenocopy presentations. In continuation with this observation, we analyzed a small cohort of 39 patients with HD phenocopy syndrome and detected the C9orf72 expansion in one female patient (2.6%) with two-year lasting mild generalized chorea and severe oro-bucco-lingual dyskinesia, who complained on forgetfullness (neuropsychological testing revealed dysexecutive syndrome with preserved episodic memory and recognition), unexplainable fears and increased appetite. Our results confirmed a possible role of the C9orf72 expansion in the genetic background of HD phenocopy syndrome.
authors.affiliation: Institute of Neurology CCS, School of Medicine, University of Belgrade, Ul. Dr Subotića 6, 11000, Belgrade, Serbia, vladimir.s.kostic@gmail.com.
authors.forename: Vladimir S
authors.initials: VS
authors.lastname: Kostić
authors.forename: Valerija
authors.initials: V
authors.lastname: Dobričić
authors.forename: Iva
authors.initials: I
authors.lastname: Stanković
authors.forename: Vesna
authors.initials: V
authors.lastname: Ralić
authors.forename: Elka
authors.initials: E
authors.lastname: Stefanova
mesh_terms: D000328:Adult; D000368:Aged; D000073885:C9orf72 Protein; D005260:Female; D019788:Fluorodeoxyglucose F18; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005820:Genetic Testing; D006801:Humans; D006816:Huntington Disease / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D049268:Positron-Emission Tomography; D011506:Proteins / Q000235:genetics*; D019680:Trinucleotide Repeat Expansion / Q000235:genetics*; D055815:Young Adult
chemical_list: D000073885:C9orf72 Protein; C568651:C9orf72 protein, human; D011506:Proteins; D019788:Fluorodeoxyglucose F18