SPG4‐related hereditary spastic paraplegia: frequency and mutation spectrum in Brazil

To the Editor : Hereditary spastic paraplegia (HSP) is a heterogeneous group of neurodegenerative disorders characterized by progressive lower limb spasticity and weakness. Mutations in SPAST /SPG4 are the major cause of autosomal dominant (AD-HSP) in Europe accounting for 40–50% of all patients (1). However, there are few studies on SPG4-HSP from Latin America (2), which has a distinctive ethnic background (populations from European, African and Native American descent). Therefore, our aim was to investigate the frequency and mutation spectrum of SPG4-HSP in a cohort of 55 Brazilian patients with AD-HSP from 34 unrelated families. Patients were recruited from three centers in the south and southeast of Brazil: Universidade Estadual de Campinas (23 families), Universidade Federal do Paraná (7) and Universidade Federal do Rio Grande do Sul (4). This study was approved by our institution Ethics Committee and written informed consent was obtained from all participants. Genomic DNA was used in polymerase chain reactions with primers designed to cover the 17 exons of SPAST /SPG4 (3). Mutation screening was performed by automatic Sanger sequencing and multiplexligand probe amplification (MLPA). All variants found were checked in human single nucleotide polymorphism (SNP) and mutation databases: Ensembl (www.ensembl.org), Human Gene Mutation Database