Supplemental material is available at https://jnnp.bmj.com/content/jnnp/93/3/336/DC1/embed/inline-supplementary-material-1.pdf?download=true . This work was supported by grants from SRC/VR 529-2014-7504, VR 2015-02926, VR 2018-02754, VR 2019-02248: JPND GENFI-PROX, the Swedish FTD Initiative-Schörling Foundation, Swedish Alzheimer Foundation, Swedish Brain Foundation, Demensfonden, Stohnes foundation, Gamla Tjänarinnor, Karolinska Institutet Doctoral funding and ALF-Region Stockholm. This work was also supported by the MRC UK GENFI grant (MR/M023664/1), the Bluefield Project, the JPND GENFI-PROX grant (2019-02248), the Dioraphte Foundation (grant numbers 09-02-00); the Association for Frontotemporal Dementias Research Grant 2009; The Netherlands Organization for Scientific Research (grant HCMI 056-13-018); ZonMw Memorabel (Deltaplan Dementie, project numbers 733 050 103 and 733 050 813); and JPND PreFrontAls consortium (project number 733051042). JDR was supported by an MRC Clinician Scientist Fellowship (MR/M008525/1) and received funding from the NIHR Rare Disease Translational Research Collaboration (BRC149/NS/MH). Several authors of this publication are members of the European Reference Network for Rare Neurological Diseases (Project ID No 739510).