Childhood disintegrative disorder (CDD), also known as Heller's syndrome and disintegrative psychosis, is a progressive condition, characterized by the regression of social, motor, and language skills by a late onset, after 2 years of age. Prevalence rates of CDD are estimated to be between 1.1 and 9.2 per 100,000, which is approximately 100 times rarer than autism spectrum disorder (ASD). CDD share features with ASD; however, there are notable features distinguishing them (Sullivan et al., 2024). CDD usually occurs between 3 and 4 years of age, after a period of seemingly normal development. The CDD regression can be gradual or abrupt, and is followed by periods of behavioral disruption with intense agitation, fearfulness, and hallucination (Wen et al., 2017). CDD is mainly diagnosed when the caregivers complain about the child's loss of previously acquired skills. The doctor will first give the child a medical examination to rule out any organic cause. Upon exclusion of such factors, referral to psychiatrist may result in the differential diagnosis of CDD (Shirazi et al., 2016).

The etiology of CDD remains unclear, but may involve genetic, immunologic, or environmental factors (Gupta et al., 2017; Wen et al., 2017). The association of CDD with various neurological and metabolic disorders, such as neurolipidosis, tuberous sclerosis, and subacute sclerosing panencephalitis, underscores the potential roles of genes in the etiology of CDD (Gupta et al., 2017). From a genetic perspective, CDD remains poorly understood. Although multiple studies have investigated genetic contributions, no single causative gene or consistent molecular mechanism has been identified. Whole-exome sequencing has revealed rare and heterogeneous variants, including genes related to synaptic function and neurodevelopment, but these findings lack replication and clear pathogenicity across cohorts (Gupta et al., 2017; Wen et al., 2017). Structural variants such as deletions involving the SHANK3 locus (22q13.3) have been reported in isolated cases with regression phenotypes overlapping CDD, though these alterations are more commonly linked to broader autism spectrum disorders (Philippe et al., 2015). Notably, many individuals with CDD show no identifiable pathogenic variants despite extensive genetic testing, indicating substantial genetic heterogeneity or non-genetic contributions (Furley et al., 2023; Gupta et al., 2017). This absence of a consistent genetic signature distinguishes CDD from monogenic regression disorders and supports the role of environmental or psychosocial triggers in vulnerable individuals (Ellis et al., 2022; Mehra et al., 2019).

Non-genetic factors, such as environmental factors, are implicated in ASD etiology; however, their exact role in CDD remains undetermined (Karimi et al., 2017). For instance, CDD has been reported as a complication of chicken pox infection in a case study (Mohapatra, 2016). Interestingly, a brief report has reported CDD as a likely manifestation of vitamin B12 deficiency (Malhotra et al., 2013). Children exposed to adverse childhood experiences are more likely to suffer from negative health outcomes, such as depression, anxiety, PTSD, and poor psychosocial functioning (Levi-Belz et al., 2025; Shaked-Ashkenazi et al., 2025), especially those with neurodevelopmental disorders, such as ADHD and autism (Davidsson et al., 2025). Although very rare, psychosocial events triggering the onset of CDD symptoms have been reported (Mehra et al., 2019).

Pediatric nurses are often the first to detect psychosocial and traumatic events that can trigger psychiatric problems in children, which underscores their importance in practice. Despite the citical role of pediatric nurses in early screening, monitoring developmental regression, and providing trauma-informed care and family support, there is a lack of clear nursing-specific guidance for the screening, management, and preventive support of children with CDD (Ellis et al., 2022).

Herein, we aim to highlight not only a rare disease but also an unusual and severe trigger for its onset. We present a case who developed CDD following a traumatic experience. We also aim to explore genetic causes of CDD in this case, along with her sleep pattern and regression.