A disease concept model of Hao-Fountain syndrome

Hao-Fountain syndrome is a rare autosomal dominant neurodevelopmental disorder caused by pathogenic variants in the USP7 gene. While its molecular and clinical spectrum has been increasingly characterized, limited research exists on the lived experience of affected individuals and their caregivers. This study develops a disease concept model (DCM) for Hao-Fountain syndrome through qualitative analysis of semi-structured interviews with 17 caregivers, one adult patient, two healthcare professionals, and one educator. Symptoms, Individual Impacts, Caregiver Impacts, Modifying Factors, and Medical Interventions were categorized and analyzed. Speech delay and global developmental delay emerged as symptoms reported across all literature and nearly all interviews. We broaden the spectrum of cognitive symptoms of this disorder, and identify novel symptoms, including speech impediment, abnormal crying, and frustration, which were frequently reported by caregivers, yet unreported in the literature. Emotional emerged as a domain containing many novel symptoms, including late-onset schizophrenia. Caregivers emphasized the profound impact of this disorder on affected individuals in the domains of Education and Work, Social and Family, Overall Health, Self-care and Daily Living, and Therapies. Assistance with activities of daily living: requires partial support emerged as a frequently reported impact which included numerous novel concepts such as assistance needed with dressing, bathing (includes all hygiene), and household tasks. Caregivers also emphasized the impact of this disorder on their own lives, including Social Impact, Emotional Impact, Effort Requirement, Financial Impact, Health Impact, and Daily Living Impact. Modifying Factors provided further insight into factors that affect lived experience of this disorder, including concepts in the domains of Family and Community Support, Access to Resources, Work, Health Support, and Resilience. Regional differences in access to services, insurance and medical care emerged as a frequently reported concept that has the ability to produce inequities in care for this patient population. By integrating caregiver and professional perspectives, this study provides a comprehensive framework to guide future research, clinical trials, and standards of care in this population.