Osteogénesis imperfecta III: a propósito de un caso de difícil diagnóstico

Introduction: osteogenesis imperfecta (OI) is a rare genetic disorder of type I collagen structure and synthesis. Its global incidence is 1 in 10.000 to 20.000. Mutations in genes COL1A1 and COL1A2 cause 90% of cases. Objective: to report a heterogeneous, difficult to diagnose case of osteogenesis imperfecta type III. Case Report: a 3-year-old male patient, son of nonconsanguineous parents, with prenatal ultrasound diagnosis of type I skeletal dysplasia and multiple long bone fractures since birth, also featuring blue sclerae, ocular proptosis, increased head anteroposterior diameter, short and deformed extremities and generalized hypotonia. Complete next generation sequencing (NGS) of the COL1A2 genes identified a probably pathogenic heterozygous variant in gene COL1A2 c.2863g>A p(Gly955Ser). Discussion: this variant is associated with type II, III and IV OI; however, the age of survival, and the presence of multiple long bone fractures since birth, bone deformity, blue sclerae, dentinogenesis imperfecta, hypotonia and absent acoustic reflexes, are manifestations associated with OI III, although patient also presents with less frequent clinical features, such as ocular proptosis and normal stature. Conclusion: making a timely diagnosis and providing treatment and genetic counseling and parental education, is important.