Younger age of onset in familial amyotrophic lateral sclerosis is a result of pathogenic gene variants, rather than ascertainment bias.
Puja R MehtaAshley R JonesSarah Opie-MartinAleksey ShatunovAlfredo IacoangeliAhmad Al KhleifatBradley N SmithSimon ToppKaren E MorrisonPamela J ShawChristopher E ShawSarah MorganAlan PittmanAmmar Al-ChalabiPublished in: Journal of neurology, neurosurgery, and psychiatry (2018)
People with familial ALS have an age of onset about 5 years younger than those with apparently sporadic ALS, and we have shown that this is a result of Mendelian gene variants lowering the age of onset, rather than ascertainment bias.