Bone dysplasias in 1.6 million births in Argentina.

Currently accepted birth prevalence for osteochondrodysplasias (OCDs) is about 2 per 10,000 births. Our main goal is to estimate the prevalence of OCDs in Argentina and compare it with other surveillance systems. We examined 1,663,610 births among 160 hospitals of RENAC (Red Nacional de Anomalías Congénitas - National Network of Congenital Anomalies) between November 2009 and December 2016. Cases were detected and registered according to a pre-established protocol, ranked in three diagnostic evidence levels according to available clinical documentation, and categorized according to the 9th edition of the nosology and classification of genetic skeletal disorders. Within our dataset, the most frequent groups were Group-1 (FGFR3, chondrodysplasia) and Group-25 (Osteogenesis Imperfecta and decreased bone density). Birth prevalence per 10,000 for the main OCD types, were: Achondroplasia 0.47 (95% CI: 0.38-0.59), Thanatophoric Dysplasia 0.37 (95% CI: 0.29-0.48), and the Osteogenesis Imperfecta group 0.34 (95% CI: 0.26-0.44). For total OCD, birth prevalence was 2.20 per 10.000 births (95% CI: 1.98-2.44). RENAC prevalence of total OCDs was found to be lower than that reported by the Latin-American Study of Congenital Malformations (ECLAMC) and Utah Birth Defect Network but higher than EUROCAT. Our investigation is the first study of OCD prevalence in Argentina using data from every jurisdiction of the country.