Manejo de fractura en hueso patológico en la infancia: picnodisostosis / Management of fractures in pathological bone in childhood: pycnodysostosis

La picnodisostosis es una enfermedad poco común que pertenece a las displasias esqueléticas que presentan fragilidad ósea y fracturas frecuentes. Radiológicamente se caracteriza por incremento de la densidad y fragilidad óseas. OBJETIVO: Presentar el caso de un escolar con displasia esquelética con fracturas en hueso patológico y manejo quirúrgico. CASO CLÍNICO: Escolar de sexo femenino, con antecedente de picnodisostosis detectado en etapa preescolar. Consulta posterior a caída de bicicleta con fractura de ambos fémures que se manejan quirúrgicamente con placa de compresión bloqueada.

Pycnodysostosis is a rare condition within skeletal dysplasias presenting with brittle bones and frequent fractures. Radiologically, it is characterised by increased bone density and fragility. OBJECTIVE: To present the case of a primary schoolchild with skeletal dysplasia with pathological bone fractures and their surgical management. CASE REPORT: A female primary schoolchild with a history of pycnodysostosis detected during the pre-school period. She was seen after bicycle fall that resulted in the fracture of both femurs, that were surgically managed with a locking compression plate.

Geografía génica de Chile: Distribución regional de los aportes genéticos americanos, europeos y africanos / Gene geography of Chile: Regional distribution of American, European and African genetic contributions

Background: The geographical distribution of genes plays a key role in genetic epidemiology. The Chilean population has three major stem groups (Native American, European and African). Aim: To estimate the regional rate of American, European and African admixture of the Chilean population. Subjects and Methods: Forty single nucleotide polymorphisms (SNP´s) which exhibit substantially different frequencies between Amerindian populations (ancestry-informative markers or AIM´s), were genotyped in a sample of 923 Chilean participants to estimate individual genetic ancestry. Results: The American, European and African individual average admixture estimates for the 15 Chilean Regions were relatively homogeneous and not statistically different. However, higher American components were found in northern and southern Chile and higher European components were found in central Chile. A negative correlation between African admixture and latitude was observed. On the average, American and European genetic contributions were similar and significantly higher than the African contribution. Weighted mean American, European and African genetic contributions of 44.34% ± 3 9%, 51.85% ± 5.44% and 3.81% ± 0.45%, were estimated. Fifty two percent of subjects harbor African genes. Individuals with Aymara and Mapuche surnames have an American admixture of 58.64% and 68.33%, respectively. Conclusions: Half of the Chilean population harbors African genes. Participants with Aymara and Mapuche surnames had a higher American genetic contribution than the general Chilean population. These results confirm the usefulness of surnames as a frst approximation to determine genetic ancestry.