SATB2-associated syndrome (SAS) is a rare genetic condition characterized by developmental delay and typical features. Currently, an evidence-based clinical practice guideline (CPG) is being developed by European Reference Network ITHACA in close collaboration with the patient community. To ensure that the guideline addresses the most pressing concerns of affected individuals, families, and clinicians, while remaining feasible to produce, a prioritization process was carried out. The prioritization process aimed to minimize the relevant clinical questions to a maximum of 12, based on criteria that were defined beforehand and based on input from a large patient community. The prioritization process included a SAS community-wide survey that collected all patient-relevant topics, a prioritization round using a tool that helps to calculate the items that were most voted on, and a final consensus round with the guideline core group. In the first round, a total of 376 topics was collected based on input from over 20 families. These were combined and refined into 48 clinical topics. A total of 269 valid responders filled in their prioritization on these topics in an online survey. Of these respondents, 234 identified as representative/family/carer, 30 identified as clinician, and 5 individuals identified as both. Rather than prioritizing a subset of 12 topics, that each would be answered with a systematic review, the core group decided on a final set of 22 questions and only 1 systematic review. Despite using a rigorous, community-driven process with input from many parents, carers, and global clinical experts, the guideline core group could not agree on a final set of 12 clinical topics. The group concluded that completeness and clinical usability of the guideline should take precedence over adhering to 12 prioritized clinical topics that could each be answered with a systematic search in the literature. We concluded that completeness and usability, vs methodological rigor, are competing interests in CPG development. This methodological issue is a pressing matter in the field of rare disease CPG development, and possibly also beyond the context of rare diseases, for which no clear solution currently exists. SATB2-associated syndrome (SAS) is a rare genetic condition that causes developmental delays and other characteristic features. A new clinical practice guideline (CPG) for SAS is currently being developed by the European Reference Network ITHACA, together with families, caregivers, and health-care professionals. To make sure the guideline focuses on the most important needs of the SAS community, a structured process was used to decide which clinical topics should be included. First, families across the SAS community were asked to share their concerns. This resulted in 376 topics, which were combined into 48 broader clinical themes. Next, 269 people completed an online survey to rank these topics. Most respondents were family members or caregivers, and some were clinicians. Finally, the guideline development team reviewed the results and discussed which topics should be prioritized. Although the original goal was to select 12 questions to answer through systematic reviews, the team decided that limiting the guideline to only 12 topics would leave out important issues. Instead, they agreed on 22 key questions, which would be addressed with only 1 systematic review. The CPG recommendations would then be more complete but supported with less systematically searched evidence. This experience highlights an ongoing challenge in rare disease guideline development: balancing completeness and practicality with strict methodological standards.

SATB2-associated syndrome (SAS) is a multisystemic disorder characterized by developmental delay, moderate to profound intellectual disability, speech delay and/or absent speech, behavioral issues such as autistic tendencies, agitation or aggressive outbursts, self-injury, impulsivity, hyperactivity, anxiety and sleeping difficulties. Alterations in the SATB2 gene have been identified as pathogenic causes of SAS. No formal clinical diagnostic criteria have been established for SAS, and molecular disruption of SATB2 is necessary to confirm the diagnosis. To investigate the molecular pathogenesis of five sporadic patients with intellectual disability, and to delineate the comprehensive clinical characteristics of SAS patients. Whole-exome sequencing analysis was performed in five unrelated patients, and RNA analysis was employed to validate the impact of genetic variation on aberrant splicing. Five SATB2 variants were identified, three of which were novel, including three frameshift variants, one nonsense variant, and a missense variant resulting in aberrant splicing was verified by RNA analysis. A comparative analysis was conducted between the clinical features of our patients and those reported in the literature. In addition to intellectual disability and impaired speech, abnormalities in palmar creases and postnatal growth delay were highlighted as clinically significant features for the diagnosis of SAS. Language regression, as well as joints and fingers abnormalities were also observed in our cohort. Our findings demonstrate that effective mRNA analysis is helpful for understanding the pathogenic mechanisms of novel variants. This study broadens the genetic and phenotypic spectrum of SAS and enhances our knowledge to facilitate accurate genetic counseling and appropriate treatment options.

SATB2-associated syndrome is an autosomal dominant neurodevelopmental syndrome caused by genetic alterations in the transcription factor SATB2. The associated phenotype is variable, and genotype-phenotype correlation studies have not yet been able to explain differences in severity and symptoms across affected individuals. While haploinsufficiency is the most often described disease mechanism, with the majority of variants consisting of whole- or partial-gene deletions and protein truncating variants with predicted loss of function, approximately one-third of affected individuals carry a SATB2 missense variant with an unknown effect. In this study, we sought to functionally characterize these missense variants to uncover associated pathogenic mechanisms. We combined a set of human cell-based experiments to screen 31 etiological SATB2 missense variants for effects on nuclear localization, global chromatin binding, and transcriptional activity. Our data indicate partial loss-of-function effects for most of the studied missense variants but identify at least eight variants with increased SATB2 function showing a combination (or subset) of features that include stronger co-localization with DNA, decreased nuclear protein mobility suggesting increased overall chromatin binding, and maintained or increased transcriptional activity. These results demonstrate that phenotypes associated with variants in SATB2 may have distinct underlying disease mechanisms, and the data could provide a resource for future studies investigating disease variability and potential therapies for this condition.

SATB2 is an AT-rich DNA-binding protein with a highly restricted expression pattern, primarily found in the brain, digestive tract, bone, and immune system, making it a promising target for medical research and clinical applications. Dysregulation or mutations in SATB2 have been implicated in various conditions, including cancers, isolated cleft palate, and SATB2-associated syndrome (SAS). This review aims to provide a comprehensive summary of the structure, biological functions, and potential role of SATB2 in tumor development. SATB2 influences gene regulation through epigenetic modulation, impacting various biological activities, including cell differentiation and immune responses. Recent studies have increasingly recognized its roles in tumorigenesis, including its contributions to cancer progression and metastasis. Moreover, SATB2 shows promise as a diagnostic marker and therapeutic target in oncology and bone-related disorders. Understanding its precise mechanisms in these contexts can pave the way for future advancements in therapeutic strategies. This review highlights the current state of knowledge on the roles of SATB2 and discusses its structural characteristics, biological functions, and potential implications in tumor development.

SATB2-associated syndrome (SAS) results from various mutations of the SATB2 gene and associates a neurodevelopmental disorder including major speech delay, intellectual disability, and behavioral problems with dental anomalies, sometimes a cleft palate, risk of osteoporosis, and facial dysmorphism. The principal objective of this study was to describe the oral phenotype of young children with SATB2-associated syndrome, especially in terms of orofacial malformation of Robin Sequence (RS) spectrum (bifid uvula, cleft palate, or RS, dental malformation, feeding and communication, with data from a national cohort. The secondary objective was to determine whether feeding and communication disorders were more severe when associated with an orofacial malformation of RS spectrum. We conducted a retrospective cross-sectional study among the largest possible cohort of patients with a mutation of the SATB2 gene in France. A questionnaire completed by the referring physicians and by telephone with parents enabled us to collect the following clinical information: (1) orofacial morphology, feeding difficulties, and pharyngeal functioning from birth to 3 years, (2) communication and language from 0 to 6 years, (3) speech development at the last examination. The study included 40 patients. Early and persistent feeding difficulties were found in 55% of the children. Communication was abnormal from the first months of life, with poor babbling in 85% of them. A major language delay was described in all patients; 65% had a vocabulary of 10 words or less. An anomaly of RS spectrum was found in half the cases, and dental malformations were described in 90%. Feeding difficulties and language delay were greater in the group with one or more orofacial malformations than the group with none. This study confirmed the severity of oral involvement, affecting feeding and speech simultaneously, in individuals with SAS. It raises the question of why the oral phenotype involving feeding and speech is more severe in the presence of cleft palate or RS. We recommend close monitoring of prelanguage communication in infants with apparently isolated cleft palate or RS and the search for SATB2 impairment when a cleft palate or RS is found, especially in the prenatal period.