Frontotemporal dementia-amyotrophic lateral sclerosis syndrome locus on chromosome 16p12.1-q12.2: genetic, clinical and neuropathological analysis

Acta Neuropathol. 2013 Apr;125(4):523-33. doi: 10.1007/s00401-013-1078-9. Epub 2013 Jan 22.

Abstract

Numerous families exhibiting both frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) have been described, and although many of these have been shown to harbour a repeat expansion in C9ORF72, several C9ORF72-negative FTD-ALS families remain. We performed neuropathological and genetic analysis of a large European Australian kindred (Aus-12) with autosomal dominant inheritance of dementia and/or ALS. Affected Aus-12 members developed either ALS or dementia; some of those with dementia also had ALS and/or extrapyramidal features. Neuropathology was most consistent with frontotemporal lobar degeneration with type B TDP pathology, but with additional phosphorylated tau pathology consistent with corticobasal degeneration. Aus-12 DNA samples were negative for mutations in all known dementia and ALS genes, including C9ORF72 and FUS. Genome-wide linkage analysis provided highly suggestive evidence (maximum multipoint LOD score of 2.9) of a locus on chromosome 16p12.1-16q12.2. Affected individuals shared a chromosome 16 haplotype flanked by D16S3103 and D16S489, spanning 37.9 Mb, with a smaller suggestive disease haplotype spanning 24.4 Mb defined by recombination in an elderly unaffected individual. Importantly, this smaller region does not overlap with FUS. Whole-exome sequencing identified four variants present in the maximal critical region that segregate with disease. Linkage analysis incorporating these variants generated a maximum multipoint LOD score of 3.0. These results support the identification of a locus on chromosome 16p12.1-16q12.2 responsible for an unusual cluster of neurodegenerative phenotypes. This region overlaps with a separate locus on 16q12.1-q12.2 reported in an independent ALS family, indicating that this region may harbour a second major locus for FTD-ALS.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Amyotrophic Lateral Sclerosis / genetics*
  • Amyotrophic Lateral Sclerosis / metabolism
  • Amyotrophic Lateral Sclerosis / pathology
  • Brain / metabolism
  • Brain / pathology*
  • Chromosomes, Human, Pair 16*
  • DNA-Binding Proteins / metabolism
  • Female
  • Frontotemporal Dementia / genetics*
  • Frontotemporal Dementia / metabolism
  • Frontotemporal Dementia / pathology
  • Genetic Linkage
  • Genetic Predisposition to Disease
  • Haplotypes
  • Humans
  • Lod Score
  • Male
  • Middle Aged
  • Phosphorylation
  • tau Proteins / metabolism

Substances

  • DNA-Binding Proteins
  • tau Proteins