Abstract|Motor Neuron Disease 1| Volume 357, SUPPLEMENT 1, e49, October 15, 2015

C9ORF72 repeated expansion in patients with familial amyotrophic lateral sclerosis from a Brazilian research center. A preliminary report

      Background: The expanded GGGGCC hexanucleotide repeat in the non-coding region of the chromosome 9 open reading frame 72 (C9ORF72) gene is the most common genetic abnormality in familial amyotrophic lateral sclerosis (FALS).
      Objective: To determine the C9ORF72 hexanucleotide repeat expansion in FALS patients from ALS Unit of São Paulo, Brazil.
      Patients and methods: Patients with FALS from the ALS Unit of Clinics Hospital, University of São Paulo Medical School, Brazil have been evaluated for the presence of an expanded (GGGGCC) in C9ORF72. A repeat-primed-PCR reaction was applied to provide a qualitative assessment of the expansions. PCR products were analyzed on an ABI3730 and visualized using GeneMapper-software. A cutoff of >30 repeats combined with a typical sawtooth pattern was considered pathologic.
      Results: Preliminaries results from 15 FALS patients (mean age of onset 51.40 ± 3.02 years) are shown. The repeat expansion was present in 5 FALS cases (33.3%) and 10 FALS did not present the pathologic expansion. One patient with C9ORF72 expansion presented a bulbar-onset and developed later a frontotemporal degeneration. Patients without C9ORF72 expansion had a spinal-onset disease. FALS patients with C9ORF72 expansion developed a later onset symptoms (54.80 ± 4.16 years) when compared to FALS without expansion (49.7 ± 4.07 years). A shorter lifespan was screen in C9ORF72 expansion carriers (5.0 ± 1.22 years) than C9ORF72 negative (9.10 ± 2.42 years).
      Conclusion: A high frequency of C9ORF7 expansion was detected in this partial report of a small FASL sample of São Paulo ALS Unit. Supported by FAPESP and CNPq, Brazil.