title: Familial segmental spinal myoclonus: a rare clinical feature of Friedreich's ataxia.
abstract: BACKGROUND
  Friedreich's ataxia (FRDA) is the most common autosomal recessive inherited ataxia. It is characterized by onset before the age of 25 year, progressive limb and truncal ataxia, lower limb areflexia, extensor plantars, dysarthria and impaired posterior column sensations. Other important associated features are skeletal deformity, hypertrophic cardiomyopathy and diabetes mellitus. Most of the patients (98%) have an unstable homozygous trinucleotide (GAA) expansion in intron-1 of chromosome 9 and 2% patients are compound heterozygous for GAA expansion and point mutations.
  
  
  METHODS
  We observed an adolescence onset FRDA exhibiting spinal segmental myoclonus (SSM) in a family. Triplet repeat primed polymerase chain reaction (TP-PCR) demonstrated unstable expansion of >66 GAA repeats.
  
  
  CONCLUSIONS
  SSM is a unique and rare manifestation of FRDA. This might be the first case report of SSM in FRDA patient.
authors.affiliation: Department of Neurology, Sawai Man Singh Medical College, Jaipur, Rajasthan India.
authors.forename: Rajendra Singh
authors.initials: RS
authors.lastname: Jain
authors.affiliation: Department of Neurology, Sawai Man Singh Medical College, Jaipur, Rajasthan India.
authors.forename: Sunil
authors.identifier: 0000-0002-4405-4444
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Department of Radiology, Sawai Man Singh Medical College, Jaipur, Rajasthan India.
authors.forename: Shankar
authors.initials: S
authors.lastname: Tejwani
keywords: Atypical phenotype; Frataxin gene; Friedreich ataxia; Segmental spinal myoclonus