ELMO2 biallelic pathogenic variants in a patient with gingival hypertrophy and cherubism phenotype: Case report and molecular review.

Ramon syndrome (OMIM #266270) was first described in a patient with cherubism, gingival fibromatosis, epilepsy, intellectual disability, hypertrichosis, and stunted growth. In 2018, Mehawej et al. described a patient with Ramon syndrome in whom a homozygous variant in ELMO2 was identified, suggesting that this gene may be the causative for this syndrome. ELMO2 biallelic pathogenic variants were also described in patients with a primary intraosseous vascular malformation (PIVM; OMIM #606893). These patients presented gingival bleeding and cherubism phenotype. Herein, a patient with gingival hypertrophy, neurodevelopmental delay, and cherubism phenotype with a novel homozygous predicted loss-of-function (LOF) variant in the ELMO2 gene and family recurrence was reported. A surgical approach to treat gingival bleeding and mandible vascular malformation was also described. Furthermore, this study includes a comprehensive literature review of molecular data regarding the ELMO2 gene. All the variants, except one described in the ELMO2, were predicted as LOF, including our patient's variant. There is an overlapping between PIVM, also caused by LOF biallelic variants in the ELMO2 gene, and Ramon syndrome, which can suggest that they are not different entities. However, due to a limited number of cases described with molecular evaluation, it is hard to establish a genotype-phenotype correlation. Our study supports that LOF pathogenic biallelic variants in the ELMO2 gene cause a phenotype that has cherubism and gingival hypertrophy as main characteristics.

Retinal changes and tumorigenesis in Ramon syndrome: follow-up of a Brazilian family.

We report on the clinical evolution of the Brazilian family with Ramon syndrome described by de Pina-Neto et al. [1986, Am J Med Genet 25:441-443]. Three members (patients IV-2, IV-18, and IV-19) have developed pigmentary changes in the retina and paleness of the optic disk. Patient IV-18 also has developed giant hypertrophy of the labia minora that, when examined histopathologically, was found to be due to neoplastic fibroblast and epithelial proliferation caused by a fibromatous process similar to that reported in the gingivae of the patients with this syndrome. Audiologic function of patient IV-2 was normal, and no skin lesions were detected. The articular signs and symptoms show that the affected relatives developed rheumatoid arthritis, which is currently inactive in patient IV-18, whereas patient IV-2 did not develop these alterations.