Background: PACS1 neurodevelopmental disorder (PACS1-NDD) (MIM# 615009) is a rare autosomal dominant disease characterized by neurodevelopmental delay, dysmorphic facial features, and congenital malformations. Heart disease (HD) is frequently present in individuals with PACS1-NDD, but a compressive review of these anomalies and an evaluation of cardiac function in a cohort of patients are lacking. Methods: (i) Cardiac evaluation in 11 PACS1-NDD patients was conducted using conventional echocardiography. (ii) Heart function was assessed by tissue Doppler imaging, and two-dimensional speckle tracking was performed in seven patients and matched controls. (iii) This systematic review focused on determining HD prevalence in individuals with PACS1-NDD. Results: In our cohort, 7 of 11 patients presented HD. (Among them, three cases of ascending aortic dilatation (AAD) were detected and one mitral valve prolapse (MVP).) None of the patients showed echocardiographic pathological values, and the left global longitudinal strain was not significantly different between patients and controls (patients −24.26 ± 5.89% vs. controls −20.19 ± 1.75%, p = 0.3176). In the literature review, almost 42% (42/100) of individuals with PACS1-NDD reportedly experienced HD. Septal defects were the most common malformation, followed by patent ductus arteriosus. Conclusions: Our results show a high prevalence of HD in PACS1-NDD patients; in this way, AAD and MVP are reported for the first time in this syndrome. Furthermore, a detailed cardiac function evaluation in our cohort did not reveal evidence of cardiac dysfunction in individuals with PACS1-NDD. Cardiology evaluation should be included for all individuals with Schuurs-Hoeijmakers syndrome.

Despite significant advances in gene discovery, the molecular basis of many rare genetic disorders remains poorly understood. The concept of disease modules, clusters of functionally related genes whose disruption leads to overlapping phenotypes, offers a valuable framework for interpreting these conditions. However, identifying such relationships remains particularly challenging in ultra-rare syndromes due to the limited number of documented cases. We hypothesized that AI-based facial phenotyping could aid in identifying shared molecular mechanisms by detecting phenotypic convergence among clinically related syndromes. To test this, we used Schuurs–Hoeijmakers syndrome (SHMS; OMIM #615009), caused by a recurrent de novo variant in PACS1, as a model to explore potential phenotypic and functional associations with PACS2-related disorder (DEE66; OMIM #618067) and WDR37-related disorder (NOCGUS; OMIM #618652). Facial photographs of individuals with SHMS were analyzed using the DeepGestalt and GestaltMatcher algorithms. In addition to consistently recognizing SHMS as a distinct clinical entity, the algorithms frequently matched DEE66 and NOCGUS, suggesting a shared facial gestalt. Binary comparisons further confirmed overlapping craniofacial features among the three disorders. These findings were supported by literature review, indicating clinical overlapping and potential functional associations. Overall, our results confirm the presence of consistent facial similarities among PACS1-, PACS2-, and WDR37-related syndromes and highlight the utility of AI-driven facial phenotyping as a complementary tool for uncovering clinically relevant relationships in ultra-rare genetic disorders.

PACS1, PACS2 and WDR37 form a clinical–molecular axis with overlapping neurodevelopmental phenotypes. The loss of previously acquired skills, encompassing developmental regression and neurodegenerative deterioration, has been mentioned only sporadically and has not been systematically reviewed. We conducted a systematic narrative synthesis of the literature indexed in PubMed/MEDLINE and Google Scholar, informed by relevant PRISMA principles, to identify patients in whom skill loss had been reported, assess the strength of the supporting evidence, and explore molecular mechanisms that might warrant prospective surveillance. Reports were classified as confirmed, probable, possible, or not reported according to predefined criteria. Most published reports describe patients with psychomotor delay and intellectual disability without loss of skills. Five patients with reported or suspected skill loss were identified among approximately 158 published patients, although this proportion should not be interpreted as prevalence. These cases included two patients with PACS1-related disorder, two with PACS2-related disorder, and one with WDR37-related disorder. The proposed mechanisms, including a shared autoinhibitory switch, HDAC6-dependent synaptic regulation, dynein-mediated transport and endoplasmic reticulum–mitochondria calcium handling, provide a plausible biological substrate but do not establish a causal relationship with skill loss. The available evidence does not support classifying these syndromes as primarily regressive disorders. However, the documented cases justify active surveillance and standardized longitudinal phenotypic characterization.

PACS1 Syndrome is an ultra-rare neurodevelopmental disorder characterized by intellectual disability, behavioral disturbances, and multisystem involvement. While clinical knowledge is growing, its impact on quality of life (QoL) has not been systematically evaluated, and it is critical to understand the lived experience and psychosocial well-being of these individuals beyond strictly medical outcomes. This study aimed to assess QoL in individuals aged 4–21 years with PACS1 Syndrome using the validated KidsLife scale, proxy-reported by primary caregivers, given the intellectual disabilities and communicative limitations of this population. Twenty-one participants from Spain and other countries were recruited through the Spanish PACS1 Association, and 39 questionnaires from mothers and fathers were analyzed. The KidsLife scale provides standardized scores across eight QoL domains and a global QoL index (QoLI). The mean QoLI was 48.1 ± 28.3, slightly below the median for individuals with intellectual disability, but higher than other neurodevelopmental disorders such as Cornelia de Lange Syndrome. The findings revealed a pattern: while domains related to social inclusion, rights, and physical and material well-being were relatively preserved, reflecting adequate care and access to resources, the most significant compromises were observed in autonomy-related domains, specifically self-determination, interpersonal relationships, and personal development. Most individuals showed a high degree of dependency, and those with greater dependency exhibited lower QoL scores. This situation led more than half of families to reduce their working hours, with caregiving responsibilities disproportionately falling on mothers. Although no statistically significant differences were found between parental ratings, mothers tended to report higher QoL. These findings reflect the substantial functional impact of PACS1 Syndrome and emphasize the need for multidisciplinary support to improve autonomy, social participation, and overall well-being.