title: Autosomal dominant cerebellar ataxia: frequency analysis and clinical characterization of 45 families from Portugal.
abstract: OBJECTIVE
  The relative frequency of the different autosomal dominant cerebellar ataxia (ADCA) varies widely amongst different geographic locations. Here we describe a series of 45 ADCA families from Portugal.
  
  
  METHODS
  Patients with progressive cerebellar dysfunction of autosomal dominant transmission underwent a clinical examination protocol and genetic testing for spinocerebellar ataxia (SCA)1 to Machado-Joseph disease (MJD)/SCA3, SCA6, SCA7, SCA10, SCA12, SCA17 and dentatorubral-pallidoluysian atrophy (DRPLA). We registered the clinical characteristics and frequency of each type of ataxia.
  
  
  RESULTS
  MJD/SCA3 was the most frequent ADCA (26 families, 57.8% of all families), followed by DRPLA (5 families, 11.2%), SCA7 (2 families, 4.4%), SCA2 and SCA1 (1 family each, 2.2% each); 10 families (22.2%) had no molecular diagnosis. SCA1 and SCA7 patients had African ancestry. DRPLA patients had Portuguese ancestry and were characterized by prominent anticipation and a variable combination of epilepsy, extra-pyramidal symptoms and dementia. Ophtalmoparesis, slow saccades and retinopathy were most distinctive of SCA3, SCA2 and SCA7 cases, respectively.
  
  
  CONCLUSIONS
  MJD/SCA3 was the most common ADCA in this group of families. The high frequency of DRPLA and presence of SCA1 and SCA7 cases was unexpected. The presence of these rarer ADCA types probably reflects migration phenomena, posing a challenge for differential diagnosis.
authors: Neurology Department, Hospital de Egas Moniz (CHLO), Lisbon, Portugal.
authors: J
authors: J
authors: Vale
authors: P
authors: P
authors: Bugalho
authors: I
authors: I
authors: Silveira
authors: J
authors: J
authors: Sequeiros
authors: J
authors: J
authors: Guimarães
authors: P
authors: P
authors: Coutinho
mesh_terms: D000293:Adolescent; D000328:Adult; D044383:Black People / Q000235:genetics; D002524:Cerebellar Ataxia / Q000145:classification* / Q000453:epidemiology / Q000235:genetics*; D025063:Chromosome Disorders / Q000235:genetics*; D004252:DNA Mutational Analysis; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D005799:Genes, Dominant / Q000235:genetics*; D005820:Genetic Testing; D005838:Genotype; D006801:Humans; D017827:Machado-Joseph Disease / Q000175:diagnosis / Q000235:genetics; D008297:Male; D020191:Myoclonic Epilepsies, Progressive / Q000175:diagnosis / Q000235:genetics; D011174:Portugal / Q000453:epidemiology / Q000208:ethnology; D015995:Prevalence; D044465:White People / Q000235:genetics; D055815:Young Adult