Mutations in components of the exon junction complex (EJC) are associated with neurodevelopment and disease. In particular, reduced levels of the RNA helicase EIF4A3 cause Richieri-Costa-Pereira syndrome (RCPS) and copy number variations are linked to intellectual disability. Consistent with this, Eif4a3 haploinsufficient mice are microcephalic. Altogether, this implicates EIF4A3 in cortical development; however, the underlying mechanisms are poorly understood. Here, we use mouse and human models to demonstrate that EIF4A3 promotes cortical development by controlling progenitor mitosis, cell fate and survival. Eif4a3 haploinsufficiency in mice causes extensive cell death and impairs neurogenesis. Using Eif4a3;p53 compound mice, we show that apoptosis has the most impact on early neurogenesis, while additional p53-independent mechanisms contribute to later stages. Live imaging of mouse and human neural progenitors reveals that Eif4a3 controls mitosis length, which influences progeny fate and viability. These phenotypes are conserved, as cortical organoids derived from RCPS iPSCs exhibit aberrant neurogenesis. Finally, using rescue experiments we show that EIF4A3 controls neuron generation via the EJC. Altogether, our study demonstrates that EIF4A3 mediates neurogenesis by controlling mitosis duration and cell survival, implicating new mechanisms that underlie EJC-mediated disorders.

Mutations in components of the exon junction complex (EJC) are associated with neurodevelopment and disease. In particular, reduced levels of the RNA helicase EIF4A3 cause Richieri-Costa-Pereira Syndrome (RCPS) and CNVs are linked to intellectual disability. Consistent with this, Eif4a3 haploinsufficient mice are microcephalic. Altogether, this implicates EIF4A3 in cortical development; however, the underlying mechanisms are poorly understood. Here, we use mouse and human models to demonstrate that EIF4A3 promotes cortical development by controlling progenitor mitosis, cell fate, and survival. Eif4a3 haploinsufficiency in mice causes extensive cell death and impairs neurogenesis. Using Eif4a3 ; p53 compound mice, we show that apoptosis is most impactful for early neurogenesis, while additional p53-independent mechanisms contribute to later stages. Live imaging of mouse and human neural progenitors reveals Eif4a3 controls mitosis length, which influences progeny fate and viability. These phenotypes are conserved as cortical organoids derived from RCPS iPSCs exhibit aberrant neurogenesis. Finally, using rescue experiments we show that EIF4A3 controls neuron generation via the EJC. Altogether, our study demonstrates that EIF4A3 mediates neurogenesis by controlling mitosis duration and cell survival, implicating new mechanisms underlying EJC-mediated disorders. This study shows that EIF4A3 mediates neurogenesis by controlling mitosis duration in both mouse and human neural progenitors, implicating new mechanisms underlying neurodevelopmental disorders.

Patients with Richieri-Costa-Pereira syndrome (RCPS) present severe craniofacial alterations and frequently require orthodontic and surgical procedures. Thus, this study aims to describe the craniofacial relationships in patients with RCPS. Panoramic radiographs and lateral cephalometric teleradiographs of 7 patients with RCPS and 7 age- and sex-matched nonsyndromic patients were analyzed. Cephalometric measurements were used to determine the size of apical bases, the relationship between them, the pattern of craniofacial growth, and the facial heights of the patients. Interobservers' concordance was verified by intraclass coefficient. For comparison between the groups, paired t test was employed. P values <.05 indicated statistical significance. Average age of patients with RCPS was 18.5 years. Six patients were female. All patients with RCPS had Pierre-Robin sequence while 2 also presented cleft mandible. Most patients with RCPS had missing lower central incisors (100%), lower lateral incisors (85.7%), lower second premolars (85.7%), and/or upper lateral incisors (57.1%). Concordance between observers was excellent for all cephalometric measurements (0.87-0.99). Patients with RCPS presented severe craniofacial alterations when compared to control group: sella-nasion-B point (SNB) angle (73.8o ± 4.86o vs 78.85o ± 4.53o, P = .029), maxillary length (7.89 cm ± 0.58 cm vs 16.36 cm ± 0.75 cm, P = .001), mandibular length (9.90 cm ± 0.46 cm vs 20.61 cm ± 0.45 cm, P = .001), upper anterior face height (5.41 cm ± 0.50 cm vs 9.40 cm ± 0.47 cm, P = .001), lower anterior face height (5.48 cm ± 0.75 cm vs 11.66 cm ± 0.55 cm, P = .001), and posterior face height (6.70 cm ± 0.33 cm vs 13.65 cm ± 1.06 cm, P = .001). There was no difference in SNB, A point-nasion-B point, pogonion-nasion-B point, and mandibular place angles between the groups (P > .05). Patients with RCPS present deficient development of maxilla and mandible when compared with nonsyndromic patients.

Robin sequence with cleft mandible and limb anomalies, known as Richieri-Costa-Pereira syndrome (RCPS), is an autosomal recessive acrofacial dysostosis characterized by mandibular cleft and other craniofacial anomalies and respiratory complications. The aim of this cross-sectional study was to describe the hyoid and head posture of 9 individuals with RCPS using cephalometric measurements and provide a discussion about its implications in obstructive sleep apnea syndrome (OSAS). The study was conducted on lateral cephalograms of patients with RCPS and 9 selected age-matched controls in tertiary cleft center in Brazil. The cephalograms were digitized and analyzed on a software to obtain the vertical and horizontal hyoid position, its relationship with the mandible and the relation of the cranial base and postvertebral line. The t test was used for analysis of means and Levene's test for equality of variances.Cephalometric measurements H-S (vertical distance between hyoid bone and sella) (Supplemental Digital Content, Figure 1, http://links.lww.com/SCS/B247) and H-C4lp (horizontal position of the hyoid in relation to the post-pharyngeal space) showed statistically significant difference compared to controls (P < 0.05). Therefore, the hyoid bone was more inferiorly and posteriorly positioned in the study group compared with the control group. The vertebrae measurements did not present differences compared to controls. The described position of hyoid bone could be involved in the severe OSAS of RCPS patients.

Richieri-Costa-Pereira syndrome is a rare autosomal recessive acrofacial dysostosis that has been mainly described in Brazilian individuals. The cardinal features include Robin sequence, cleft mandible, laryngeal anomalies and limb defects. A biallelic expansion of a complex repeated motif in the 5' untranslated region of EIF4A3 has been shown to cause this syndrome, commonly with 15 or 16 repeats. The only patient with mild clinical findings harbored a 14-repeat expansion in 1 allele and a point mutation in the other allele. This proband is described here in more details, as well as is his affected sister, and 5 new individuals with Richieri-Costa-Pereira syndrome, including a patient from England, of African ancestry. This study has expanded the phenotype in this syndrome by the observation of microcephaly, better characterization of skeletal abnormalities, less severe phenotype with only mild facial dysmorphisms and limb anomalies, as well as the absence of cleft mandible, which is a hallmark of the syndrome. Although the most frequent mutation in this study was the recurrent 16-repeat expansion in EIF4A3, there was an overrepresentation of the 14-repeat expansion, with mild phenotypic expression, thus suggesting that the number of these motifs could play a role in phenotypic delineation.