Tooth agenesis is among the most prevalent congenital anomalies affecting human dentition, characterized by the developmental absence of one or more teeth. This condition may be present in either syndromic or non-syndromic forms, with significant implications for oral function, aesthetics, and craniofacial development. This narrative review aims to provide a comprehensive overview of tooth agenesis, defining its classification, genetic underpinnings, epidemiological aspects, phenotypic features, and therapeutic approaches. Recent advances in genetic research have identified numerous causative genes, notably EDA, MSX1, WNT10A, and PAX9, each associated with specific patterns of missing teeth and involved in isolated and/or syndromic forms. Additionally, genes such as TSPEAR, LRP6, PITX2, and GREM2 contribute to varying degrees of severity and tooth distribution, often blurring the lines between syndromic and isolated cases. The genotype-phenotype correlations underscore the complexity of the underlying molecular pathways involved in odontogenesis. From a therapeutic perspective, the management of tooth agenesis requires a multidisciplinary approach, often involving orthodontic, prosthetic, and surgical interventions tailored to the severity of tooth loss and patient age. Early diagnosis represents a crucial role in treatment planning, facilitating timely intervention during growth and enhancing long-term outcomes. In conclusion, tooth agenesis remains a complex clinical condition with a strong genetic basis. A patient-centered and interdisciplinary strategy is essential to address both functional and psychosocial needs.

Background: Periodontitis is a multifactorial inflammatory disease with a complex interplay between microbial, environmental, and host-related factors. Among host factors, genetic susceptibility plays a significant role in influencing both disease onset and progression. Over the past two decades, a wide range of genetic tests, ranging from single-nucleotide polymorphism (SNP) analysis to genome-wide association studies (GWAS), have been explored to assess individual risk profiles and potential treatment responses. However, despite initial enthusiasm, the clinical integration of genetic testing in periodontics remains limited. This narrative review aims to critically examine the current landscape of genetic testing in periodontitis, including commercially available tests, their scientific validity, and their clinical utility. Methods: Most relevant studies which were published in recent years were identified by using the major scientific search engines, including PubMed, Scopus, and Web of Science. Articles discussing genetic susceptibility, key gene polymorphisms, and emerging technologies were included in this narrative review. Results: Polymorphisms in genes coding for IL-1, IL-6, TNF-α, and in others involved in immune modulation and bone metabolism, are associated with periodontitis. Nevertheless, there are limitations related to heterogeneity in study design, population stratification, and gene–environment interactions. Moreover, emerging technologies, including polygenic risk scoring and machine learning approaches, may enhance the predictive value of genetic tools in periodontology. Conclusions: A deeper understanding of genetic susceptibility could pave the way for precision dentistry and personalized periodontal care, but significant hurdles remain before genetic testing can become a routine component of periodontal diagnostics.

Primary failure of tooth eruption (PFE) is a rare genetic disorder characterized by the failure of teeth to erupt in the absence of obvious physical obstructions, often resulting in a progressive open bite that is resistant to orthodontic treatment. While PFE can be caused by genetic or systemic factors (such as cysts, tumors, and endocrine imbalances), the non-syndromic causes are primarily genetic, with an autosomal dominant inheritance pattern with variable expressivity. Several genes have been closely associated with the non-syndromic PFE form. The PTH1R (parathyroid hormone 1 receptor) is the most commonly PFE-associated gene. Additional genes associated with minor frequency are Transmembrane protein 119 (TMEM119), which reduces the glycolytic efficiency of bone cells, limiting their mineralization capacity and causing bone fragility; Periostin (POSTN), which regulates the extracellular matrix and the bone’s response to mechanical stress; and Lysine (K)-specific methyltransferase 2C (KMT2C), which establishes histone methylation near the Wnt Family Member 5A (WNT5A) gene involved in dental development (odontogenesis). Syndromic forms of PFE are typically associated with complex multisystem disorders, where dental eruption failure is one of the clinical features of the spectrum. These syndromes are often linked to genetic variants that affect ectodermal development, craniofacial patterning, and skeletal growth, leading to abnormal tooth development and eruption patterns. Notable syndromes include GAPO syndrome, ectodermal dysplasia, and cleidocranial dysplasia, each contributing to PFE through distinct molecular mechanisms, such as disruptions in dental structure development, cranial abnormalities, or systemic developmental delays. The main aim of this review is to provide a comprehensive overview of the genetic basis underlying both syndromic and non-syndromic forms of PFE to facilitate precision diagnosis, foster the development of personalized therapeutic strategies, and offer new insights into managing this complex dental anomaly.

Background: Macrocephaly can be a component manifestation of several monogenic conditions, in association with intellectual disability/developmental delay (ID/DD) behaviour abnormalities, including autism spectrum disorders (ASD), and variable additional features. On the other hand, idiopathic ASD can present with developmental delay and macrocephaly. Methods: We carried out a retrospective analysis of a cohort of 78 patients who were tested from February 2017 to December 2024 by high-throughput sequencing of a panel of 27 genes (ABCC9, AKT1, AKT2, AKT3, BRWD3, DIS3L2, DNMT3A, EZH2, GPC3, GPC4, HERC1, MED12, MTOR, NFIA, NFIX, NSD1, PDGFRB, PIK3CA, PIK3R1, PIK3R2, PPP2R1A, PPP2R5D, PTEN, RAB39B, RNF135, SETD2, and TBC1D7) because of neurodevelopmental impairment, including ID/DD, ASD/behaviour abnormalities associated with macrocephaly, mimicking to a large extent idiopathic ASD. Results: Pathogenic variants leading to the diagnosis of monogenic conditions were detected in 22 patients (28%), including NSD1 (2), PTEN (16), and PPP2R5D (4). Distinctive of the PTEN-associated phenotype were true macrocephaly (100%), ASD or behaviour abnormalities (92%), mild/borderline ID (79%), and no facial dysmorphisms. Typical of the PPP2R5D-associated phenotype were relative macrocephaly (75%), a few unspecific peculiar facial characteristics (50%), and a more variable presentation of the neurodevelopmental phenotype. Conclusions: Pathogenic variants in PTEN and PPP2R5D are the most recurrent gene mutations in a patient-oriented procedure for the genetic diagnosis of apparently idiopathic ASD and behaviour abnormalities associated with macrocephaly. The clinical applicability of the presented diagnostic strategy is discussed.

Growth retardation, alopecia, pseudoanodontia and optic atrophy (GAPO) syndrome is a rare autosomal recessive disorder caused by biallelic pathogenic variants in the ANTXR1 gene. While significant progress has been made in understanding its molecular basis, no systematic description of the clinical phenotype is available. We conducted a comprehensive review of 105 cases reported in the available literature since the first description of GAPO syndrome in 1947. We summarise here the current understanding of the clinical phenotype and the genetic basis of the condition. Our findings point out the multisystemic nature of GAPO syndrome, primarily featuring skeletal, dermatological and ophthalmological manifestations. The condition is caused by the biallelic loss-of-function of ANTXR1 . Histological findings throughout the reported cases underscore the critical role of excessive extracellular matrix deposition in the pathogenesis of GAPO syndrome. The evidence gathered suggests ANTXR1 as an important regulator of extracellular matrix homeostasis. This study highlights the clinical and molecular spectrum of GAPO syndrome. Early recognition, multidisciplinary care and genetic counselling are essential for improving patient outcomes. Future studies should focus on targeted therapies addressing extracellular matrix dysregulation.