The molecular basis of the frontotemporal lobar degeneration-amyotrophic lateral sclerosis spectrum

Ann Med. 2012 Dec;44(8):817-28. doi: 10.3109/07853890.2012.665471. Epub 2012 Mar 16.


There is increasing evidence that frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS) represent a continuum of neurodegenerative diseases. FTLD is complicated by ALS in a significant proportion of patients, and neuropsychological studies have demonstrated frontotemporal dysfunction in up to 50% of ALS patients. More recently, advances in neuropathology and molecular genetics have started to disclose the biological basis for the observed clinical concurrence. TDP-43 and FUS have been discovered as key pathological proteins in both FTLD and ALS. The most recent discovery of a pathological hexanucleotide repeat expansion in the gene C9orf72 as a frequent cause of both FTLD and ALS has eventually confirmed the association of these two at first sight distinct neurodegenerative diseases. Mutations in the TARDBP, FUS, and VCP genes had previously been associated with different phenotypes of the FTLD-ALS spectrum, although in these cases one end of the spectrum predominates. Whilst on the one hand providing evidence for overlap, these discoveries have also highlighted that FTLD and ALS are etiologically diverse. In this review, we review the recent advances that support the existence of an FTLD-ALS spectrum, with particular emphasis on the molecular genetic aspect.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adenosine Triphosphatases / genetics
  • Amyotrophic Lateral Sclerosis / complications
  • Amyotrophic Lateral Sclerosis / genetics*
  • C9orf72 Protein
  • Cell Cycle Proteins / genetics
  • DNA Repeat Expansion
  • DNA-Binding Proteins / genetics*
  • Frontotemporal Lobar Degeneration / complications
  • Frontotemporal Lobar Degeneration / genetics*
  • Humans
  • Proteins / genetics*
  • RNA-Binding Protein FUS / genetics
  • Valosin Containing Protein


  • C9orf72 Protein
  • C9orf72 protein, human
  • Cell Cycle Proteins
  • DNA-Binding Proteins
  • Proteins
  • RNA-Binding Protein FUS
  • Adenosine Triphosphatases
  • VCP protein, human
  • Valosin Containing Protein