Implementing genetic counselling and whole genome sequencing for young onset dementia within neurology and neuropsychiatry clinics: a RE-AIM framework analysis

People with young onset dementia (YOD) often experience long diagnostic delays, including lengthy multi-step genetic testing. Whole genome sequencing (WGS) enables comprehensive genetic analysis within a single test modality. This study aimed to implement a clinical model whereby genetic counsellors joined multidisciplinary dementia clinic teams and facilitated point-of-care access to WGS. A type II hybrid implementation effectiveness design incorporating the RE-AIM theoretical framework was used. Genetic counselling facilitated patient and family decision-making, consent, and adjustment to results. WGS included analysis of single nucleotide variants, insertions/deletions and structural variants. DNA repeat expansion variants were also analysed and validated. Questionnaires and semi-structured interviews with patients, family members and health professionals were included in the evaluation. Implementation of this model with WGS as a first-line test led to a genetic diagnosis for 20 of 78 families (26%), with an average time of 8.3 months from referral to results. Patients and family members valued streamlined access to genetic counselling and genomic testing as an opportunity to better understand the cause, the condition and potential implications for relatives. Staff in dementia clinics reported improvements in perceived utility, familiarity and confidence with genomics through collaboration with genetic counsellors. Providing access to genetic counselling as part of dementia clinical teams enabled a flexible family-focused approach which was valued by staff, patients and relatives during a difficult time in their lives. WGS as a first line genetic test enables clinically relevant results in a timely manner for patients with YOD and their families.