Using Interpretative Phenomenological Analysis to Explore the Experiences of Mothers Who Have a Child With the Rare Genetic Disorder, HNRNPU-Related Neurodevelopmental Disorder: "Some Days, I Wear a Cape and I'm Super Mom and Some Days, I Have to Hide Under My Cape and I Can't Get Out for a Few Days"

HNRNPU-related neurodevelopmental disorder is an ultra-rare genetic condition characterised by developmental delay, intellectual disability, seizures and a range of complex health needs. Yet, little is known about how families experience and navigate life with this diagnosis. This study explored the lived experiences of seven mothers caring for a child with HNRNPU-NDD, using Interpretive Phenomenological Analysis of semi-structured interviews to gain an in-depth understanding of how they manage with daily life and sustain their well-being. Three group experiential themes (GETs) were generated: (1) From nurturer to care manager: how hypervigilance shapes daily life and maternal identity, (2) How mothers make sense of futures that no longer look as expected: grief, fear of future and reconstruction of hope, (3) Social worlds that 'no longer fit': experiences of isolation and disconnection. Together, these themes show the emotional duality, identity shifts and social challenges involved in raising a child with HNRNPU-NDD. They are discussed alongside existing literature on rare disease caregiving, highlighting shared challenges as well as aspects that appear distinctive to ultra-rare neurodevelopmental conditions. The findings illustrate that mothers require meaningful support acknowledging the emotional weight and relational shifts of caregiving, beyond the child's symptoms. This study aims to shed light into an under-researched condition and offer suggestions for future research which should include broader family perspectives (fathers and siblings) and the development of support systems tailored to the complex needs of this population.