The identification of both novel and previously reported pathogenic variants expands the mutational spectrum of PURA and underscores the importance of integrating clinical, molecular, and bioinformatic data for accurate variant interpretation.
Abstract
Background: PURA-related neurodevelopmental disorder (PURA-NDD; OMIM #616158) is a rare autosomal dominant condition caused by pathogenic variants in the PURA gene encoding Purα, a multifunctional protein involved in DNA replication, transcriptional regulation, and RNA transport. Since its initial description in 2014, PURA-NDD has been increasingly recognized as a distinct clinical entity with early onset and a broad phenotypic spectrum. The clinical presentation is characterized primarily by neonatal hypotonia, global developmental delay, intellectual disability, feeding difficulties, and epilepsy, along with additional features such as respiratory insufficiency, movement disorders, hypersomnolence, and variable dysmorphic traits. Despite a relatively recognizable core phenotype, marked inter-individual variability often limits the ability to establish a definitive clinical diagnosis based on phenotype alone. This underscores the essential role of molecular genetic testing in the differential diagnosis of rare neurodevelopmental disorders. Patients and methods: We report a cohort of eight individuals (four males and four females) aged 17 months to 15.5 years with PURA-related neurodevelopmental disorder (PURA-NDD), evaluated using a genotype-first diagnostic strategy supported by comprehensive genomic testing, including next-generation sequencing (NGS) panels and whole-genome sequencing (WGS). Patients were referred for the evaluation of nonspecific neurodevelopmental features, including neonatal hypotonia, respiratory distress, and epilepsy, in the absence of a definitive clinical diagnosis. Results: Molecular analysis identified eight heterozygous variants in PURA, of which four (50%) were novel: c.311T>G p.(Met104Arg), c.406_407del p.(Gln136Glyfs64), c.515A>C p.(Gln172Pro), and c.885delinsGC p.(His296Profs21). The remaining variants included previously reported missense and frameshift changes associated with PURA-NDD, as well as one variant previously reported in ClinVar. Conclusions: Our findings not only confirm the core clinical features of PURA-related neurodevelopmental disorder but also contribute to a more comprehensive delineation of its phenotypic spectrum. The detailed characterization of our cohort broadens the range of recognized clinical manifestations and further highlights the marked phenotypic heterogeneity of PURA-NDD. In addition, the identification of both novel and previously reported pathogenic variants expands the mutational spectrum of PURA and underscores the importance of integrating clinical, molecular, and bioinformatic data for accurate variant interpretation. Although genotype–phenotype correlations remain incompletely understood, emerging evidence suggests potential associations between variant type or location and clinical severity, warranting further investigation in larger cohorts. The recognition of characteristic neonatal features may facilitate earlier diagnosis and implementation of supportive multidisciplinary management. Overall, this study illustrates how genomic technologies not only improve diagnostic yield in rare disorders but also refine disease definition, enhance the understanding of underlying pathogenic mechanisms, and support the development of more precise genotype–phenotype correlations. Further studies involving larger cohorts and long-term follow-up are needed to better define the full clinical and molecular spectrum of PURA-NDD.
PPP1R21-related neurodevelopmental disorder (PPP1R21-NDD) is an ultra-rare autosomal-recessive encephalopathy caused by dysfunction of the Five-subunit Endosomal Rab5 and RNA/ribosome intermediarY (FERRY) complex. To delineate the clinical, neuroimaging, and molecular spectrum of PPP1R21-NDD and outline diagnostic and research priorities. Targeted searches of PubMed, EMBASE, Scopus, Web of Science, and Google Scholar through January 2026 were performed. Eligible reports included molecularly confirmed biallelic PPP1R21 cases and related functional studies. Two researchers independently extracted individual-level data following narrative review quality criteria. Twenty-five individuals from 21 families harbored 17 distinct variants (15 loss-of-function, 2 missense), all homozygous, reflecting high consanguinity. Profound global developmental delay/intellectual disability was universal; hypotonia near-universal (22/25, 88%). Ambulation was delayed and ataxic when achieved; expressive language was minimal or absent. A recognizable coarse facial gestalt was observed with thick eyebrows, broad nasal bridge, thick lips, and low-set ears. Systemic features included feeding dysfunction and respiratory morbidity requiring gastrostomy or tracheostomy in severe cases. Mortality was 17% (4/24). Neuroimaging showed callosal thinning, white-matter volume loss, ventricular enlargement, and vermian hypoplasia. Patient fibroblasts showed delayed transferrin clearance and elevated proteasome activity, suggesting endosomal dysfunction and proteasome hyperactivation. PPP1R21-NDD is a severe recessive encephalopathy with a convergent phenotype and evidence of endo-lysosomal dysfunction. Diagnosis should be pursued with exome or genome sequencing in patients with characteristic clinical and neuroimaging features, particularly in consanguineous families. Research priorities include natural history studies, standardized magnetic resonance imaging (MRI) protocols, neural disease models, and therapeutic strategies targeting endosomal trafficking.
F. Comisi, G. Di Pasquale, A. Comisi et al.· Neurogenetics· 0 citations
This case expands the clinical spectrum associated with RFX3 variants, supporting a potential role in IESS and early neurodevelopmental disruption, and highlights the relevance of including RFX3 in the genetic evaluation of patients with IESS and co-occurring neurodevelopmental disorders.
Graziana Ceraolo, Giulia Spoto, M. Trivisano et al.· International Journal of Mol...· 0 citations
Heterozygous variants in FBXW7 have recently been recognized as a cause of a rare neurodevelopmental disorder with variable developmental delay, neurological manifestations, and multisystem involvement. The breadth of clinical variability and penetrance remains incompletely defined. We report a retrospective multicenter case series of seven previously unreported individuals (five males, two females) with heterozygous FBXW7 variants identified through clinical genetic testing, aged 5–9 years at last evaluation (median 6 years). Six variants occurred de novo and one was inherited. Neurodevelopmental involvement was present in six individuals and was characterized by global developmental delay and language impairment; hypotonia was observed in all seven. Formal intellectual disability was documented in four cases, while one individual showed preserved cognitive functioning with predominant behavioral difficulties. Epileptic seizures occurred in four individuals, whereas three had no history of epilepsy. Brain MRI was available for six individuals and was normal in four, whereas two showed structural anomalies involving the corpus callosum. Extracerebral features were variably reported, most commonly constipation and recurrent respiratory/otolaryngological infections. Comparison with previously reported individuals confirmed the core neurodevelopmental phenotype and further refined the spectrum. This case series expands the phenotypic spectrum associated with FBXW7-related neurodevelopmental disorder and highlights variable expressivity and incomplete penetrance, including clinically relevant variants presenting with mild or atypical phenotypes. These findings support considering FBXW7 across a broad range of neurodevelopmental presentations and inform genetic counseling.
Salvatore Savasta, F. Comisi, G. Dell’Isola et al.· Journal of Neurodevelopmenta...· 0 citations
Background Pathogenic variants in the CASK gene cause a broad spectrum of X-linked phenotypes ranging from microcephaly with pontine and cerebellar hypoplasia (MICPCH) to only mild intellectual disability (ID). Variable clinical pictures pose significant diagnostic challenges. Methods We conducted a retrospective observational study with longitudinal follow-up at a tertiary pediatric neurology center over a 10-year period (6,179 patients were hospitalized and evaluated). Since 2015, genetic testing using next-generation sequencing gene (NGS) panels, including CASK gene, was performed in patients with MICPCH and the first patient was confirmed through hereditary ataxia NGS panel. Two additional patients were identified among 105 children with suspected genetic neurodevelopmental disorders undergoing CentoNeuro panel (including 1,902 genes), which was available during a period (2023–2024). Clinical, neuroimaging, and genetic data were analyzed during follow-up. Results Two female patients carried de novo loss-of-function CASK variants and presented with MICPCH, progressive developmental impairment, abnormal muscle tone, postnatal growth retardation, and epilepsy in one case. The male patient carried an inherited likely pathogenic missense variant and exhibited severe ID, drug-resistant epilepsy, autistic features, and a cerebral palsy–like phenotype without microcephaly or pontocerebellar malformations. All patients demonstrated periods of developmental arrest or regression, suggesting non-linear developmental trajectories. Marked intrafamilial phenotypic variability was observed. Conclusions CASK-related disorders may present with severe neurodevelopmental impairment and cerebral palsy–like phenotypes, even in the absence of characteristic neuroimaging findings. A cerebral palsy-like phenotype, postnatal growth retardation, and variable ID should raise suspicion for CASK-related disorders. Comprehensive genetic testing, including next-generation sequencing, is essential for accurate diagnosis.
I. Pacheva, Elena Timova, T. Todorov et al.· Frontiers in Psychiatry· 0 citations
The concept that NRXN1 deletions alone do not determine clinical outcome but rather act within a broader genetic and biological context is supported, whereby NRXN1 deletions act as susceptibility factors whose phenotypic consequences are shaped by additional genetic and modifying influences.
N. Kastratović, Marina Gazdić Janković, Marina Miletić Kovačević et al.· International Journal of Mol...· 0 citations