The Richieri-Costa and Pereira syndrome: report of two Brazilian siblings and review of literature

Craniofacial Features in Richieri-Costa-Pereira Syndrome

OBJECTIVE

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.

DESIGN

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.

RESULTS

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 (73.8^o ± 4.86^o vs 78.85^o ± 4.53^o, 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).

CONCLUSION

Patients with RCPS present deficient development of maxilla and mandible when compared with nonsyndromic patients.

Richieri-Costa-Pereira syndrome: Expanding its phenotypic and genotypic spectrum

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.

EIF4A3 deficient human iPSCs and mouse models demonstrate neural crest defects that underlie Richieri-Costa-Pereira syndrome

Biallelic loss-of-function mutations in the RNA-binding protein EIF4A3 cause Richieri-Costa-Pereira syndrome (RCPS), an autosomal recessive condition mainly characterized by craniofacial and limb malformations. However, the pathogenic cellular mechanisms responsible for this syndrome are entirely unknown. Here, we used two complementary approaches, patient-derived induced pluripotent stem cells (iPSCs) and conditional Eif4a3 mouse models, to demonstrate that defective neural crest cell (NCC) development explains RCPS craniofacial abnormalities. RCPS iNCCs have decreased migratory capacity, a distinct phenotype relative to other craniofacial disorders. Eif4a3 haploinsufficient embryos presented altered mandibular process fusion and micrognathia, thus recapitulating the most penetrant phenotypes of the syndrome. These defects were evident in either ubiquitous or NCC-specific Eif4a3 haploinsufficient animals, demonstrating an autonomous requirement of Eif4a3 in NCCs. Notably, RCPS NCC-derived mesenchymal stem-like cells (nMSCs) showed premature bone differentiation, a phenotype paralleled by premature clavicle ossification in Eif4a3 haploinsufficient embryos. Likewise, nMSCs presented compromised in vitro chondrogenesis, and Meckel's cartilage was underdeveloped in vivo. These findings indicate novel and essential requirements of EIF4A3 for NCC migration and osteochondrogenic differentiation during craniofacial development. Altogether, complementary use of iPSCs and mouse models pinpoint unique cellular mechanisms by which EIF4A3 mutation causes RCPS, and provide a paradigm to study craniofacial disorders.

A review of craniofacial disorders caused by spliceosomal defects

The spliceosome is a large ribonucleoprotein complex that removes introns from pre-mRNA transcripts. Mutations in EFTUD2, encoding a component of the major spliceosome, have recently been identified as the cause of mandibulofacial dysostosis, Guion-Almeida type (MFDGA), characterized by mandibulofacial dysostosis, microcephaly, external ear malformations and intellectual disability. Mutations in several other genes involved in spliceosomal function or linked aspects of mRNA processing have also recently been identified in human disorders with specific craniofacial malformations: SF3B4 in Nager syndrome, an acrofacial dysostosis (AFD); SNRPB in cerebrocostomandibular syndrome, characterized by Robin sequence and rib defects; EIF4A3 in the AFD Richieri-Costa-Pereira syndrome, characterized by Robin sequence, median mandibular cleft and limb defects; and TXNL4A in Burn-McKeown syndrome, involving specific craniofacial dysmorphisms. Here, we review phenotypic and molecular aspects of these syndromes. Given the apparent sensitivity of craniofacial development to defects in mRNA processing, it is possible that mutations in other proteins involved in spliceosomal function will emerge in the future as causative for related human disorders.

A noncoding expansion in EIF4A3 causes Richieri-Costa-Pereira syndrome, a craniofacial disorder associated with limb defects

Richieri-Costa-Pereira syndrome is an autosomal-recessive acrofacial dysostosis characterized by mandibular median cleft associated with other craniofacial anomalies and severe limb defects. Learning and language disabilities are also prevalent. We mapped the mutated gene to a 122 kb region at 17q25.3 through identity-by-descent analysis in 17 genealogies. Sequencing strategies identified an expansion of a region with several repeats of 18- or 20-nucleotide motifs in the 5' untranslated region (5' UTR) of EIF4A3, which contained from 14 to 16 repeats in the affected individuals and from 3 to 12 repeats in 520 healthy individuals. A missense substitution of a highly conserved residue likely to affect the interaction of eIF4AIII with the UPF3B subunit of the exon junction complex in trans with an expanded allele was found in an unrelated individual with an atypical presentation, thus expanding mutational mechanisms and phenotypic diversity of RCPS. EIF4A3 transcript abundance was reduced in both white blood cells and mesenchymal cells of RCPS-affected individuals as compared to controls. Notably, targeting the orthologous eif4a3 in zebrafish led to underdevelopment of several craniofacial cartilage and bone structures, in agreement with the craniofacial alterations seen in RCPS. Our data thus suggest that RCPS is caused by mutations in EIF4A3 and show that EIF4A3, a gene involved in RNA metabolism, plays a role in mandible, laryngeal, and limb morphogenesis.

Richieri-costa and Pereira syndrome: severe phenotype

Richieri-Costa and Pereira syndrome, described in 1992, comprises short stature, Robin sequence, cleft mandible, limb malformations, and short larynx, deformed or lack of epiglottis, and abnormal aryepiglottic folds. There are 32 reported cases, only one described outside Brazil. We describe a 4-month-old boy with the most severe phenotype yet reported.

Laryngeal malformation in Richieri-Costa Pereira syndrome: new findings

Laryngeal structural anomalies were described in 13 cases of Richieri-Costa Pereira syndrome, and four previously reported cases were reviewed. The 17 individuals examined had the typical laryngeal anomalies and vocal disorders previously described. The new findings are the laryngeal microweb observed in three cases and arytenoid anteriorization movement observed in 14 cases.