Importance of genomics in the diagnosis of new variants associated with connective tissue disorders with phenotype overlap

Abstract

Contractural arachnodactyly congenita  (CCA) is an autosomal dominantly inherited connective tissue disease caused by variants in the FBN2 gene encoding fibrillin-2. It has specific features such as congenital contractures, wrinkled upper helix ear, camptodactyly, pectus carinatum and complications such as scoliosis and kyphoscoliosis. We publish the case of a 19-year-old female patient with a history of thinness, accelerated growth velocity, tall stature, weight loss, joint contractures, congenital hypotonia, precocious puberty, marfanoid habitus, pectus carinatum and mild arachnodactyly. Collagen disease was suspected and whole exome sequencing by NGS  (Next Generation Sequencing) + CNVs  (Copy Number Variations) genes related to collagenopathies was requested; a variant was identified in the FBN2 gene  (NM_001999.4): c.4394G>A; p.Cys1465Tyr; heterozygous state of probably pathogenic clinical significance. CCA is phenotypically similar to Marfan syndrome and is characterized by arachnodactyly, dolichostenomelia, scoliosis, multiple congenital contractures, and external ear anomalies. Unlike Marfan syndrome, it has no ocular involvement and does not affect the aortic root. It has phenotypic variability that gives it heterogeneity that can interfere and delay the specific diagnostic and therapeutic process by overlapping with other medical conditions. Advances in medicine and genomics with the use of new diagnostic methods have allowed us to get closer to 6P medicine  (precision, prediction, prevention, personalized, participatory with a population approach) that impacts on the diagnosis, specific treatment, follow-up, prognosis and adequate genetic counseling of diseases.