Clinical and Molecular Characterization of Five Additional Individuals With SATB2-Associated Syndrome in Guangxi

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.