The BRAT1 gene plays a crucial role in RNA metabolism and brain development, and mutations in this gene have been associated with neurodevelopmental disorders. The variability in the clinical presentation of BRAT1-related disorders is highlighted, emphasizing the importance of considering this condition in the differential diagnosis of neurodevelopmental disorders. This study aimed to identify a causative variant in an Iranian patient affected by developmental delay, speech delay, seizure, and clubfoot through whole exome sequencing (WES) followed by Sanger sequencing. The WES revealed a novel biallelic variant of the BRAT1, c.398A>G (p.His133Arg), in the patient, which segregated within the family. A literature review suggests that the phenotypic variability associated with BRAT1 mutations is likely due to multiple factors, including the location and type of mutation, the specific functions of the protein, and the influence of other genetic and environmental factors. The phenotypic variability of BRAT1-related disorders underscores the importance of considering BRAT1-related disorders in the differential diagnosis of epileptic encephalopathy with rigidity. These findings provide important insights into the role of BRAT1 in neurodevelopmental disorders and highlight the potential clinical implications of identifying and characterizing novel variants in this gene.

Background: Psychomotor delay, epilepsy and dysmorphic features are clinical signs which are described in multiple syndromes due to chromosomal imbalances or mutations involving key genes implicated in the stages of Early Embryonic Development. In this context, we report a 10 years old Tunisian patient with these three signs. Our objective is to determine the cause of developmental, behavioral and facial abnormalities in this patient. Methods: We used banding cytogenetics (karyotype) and Array Comparative Genomic Hybridization (Array CGH) to this purpose. Results: The karyotype was in favor of a derivative of chromosome 7 in the patient and Array CGH analysis revealed a loss of genetic material in 7p22.3-p22.1 (4,56 Mb) with a gain at 8q24.23-q24 (9.20 Mb) resulting from maternal 7/8 reciprocal translocation. An in silico analysis of the unbalanced region was carried out and showed that the 7p22.3-p22.1 deletion contains eight genes. Among them, BRAT1 gene, previously described in several neurodevelopmental diseases, may be a candidate gene which absence could be correlated to the patient\'s phenotype. However, the 8q24.23-q24 duplication could be involved in the phenotype of this patient. Conclusion: In this study, we report for the first time a 7p deletion/8q duplication in a patient with psychomoteur delay, epilepsy and facial dysmorphism. Our study showed that Array CGH still useful for delivering a conclusive genetic diagnosis for patients having neurodevelopmental abnormalities in the era of next-generation sequencing.

We present a case of lethal neonatal rigidity and multifocal seizure syndrome (RMFSL) in an early-term female infant born to non-consanguineous parents. RMFSL is a recently discovered autosomal recessive disease caused by the BRAT1 gene mutations. The BRAT1 gene encodes the BRCA1-associated protein required for ATM activation-1, a protein that interacts with BRCA1 and ATM to initiate DNA repair in response to DNA damage. The exon sequence revealed biallelic deletions of exon 1-2 of the BRAT1 gene in our patient. There are only a few cases of RMFSL reported in the literature, and all of them have died before two years, mostly in the first six months of life. Our patient died at the age of 74 days.