FTD/ALS families are no longer orphaned

Abstract

The frontotemporal degenerations (FTD) are, as a group, considered as orphan diseases. A variety of clinical syndromes are encompassed by FTD, including behavioral variant FTD (bvFTD), and semantic and nonfluent/agrammatic variants of primary progressive aphasia (PPA). Motor neuron disease or amyotrophic lateral sclerosis (ALS) may co-occur in small percentages of sporadic cases, and within families with or without FTD. Very recently, hexanucleotide repeat expansions in the chromosome 9 open reading frame 72 ( C9ORF72 ) have been indentified in families with FTD with or without ALS.1,2 This is a notable discovery in neurodegenerative disease research of FTD over the last 14 years, along with the identification of microtubule-associated protein tau (MAPT) mutations, progranulin (PGRN) gene mutations, and the discovery of the TDP-43 protein as major component of ubiquitin-positive inclusions in FTD and ALS. The presence of the latter inclusions in both FTD and ALS has already lent strong support to the hypothesis that both FTD and ALS are part of a disease continuum, uniting FTD and ALS researchers in their goals. The discovery of the …