Fenotipos neurológicos en pacientes estudiados con citogenética en el Hospital de Puerto Montt / Neurological phenotypes in cytogenic study from Puerto Montt Hospital patients

El examen citogenético, es una herramienta importante para confirmar el diagnóstico, manejo y consejo genético. El objetivo es analizar las características del fenotipo neuroconductual, protocolizar y orientar en la eficaz solicitud del estudio citogenético. Se revisaron las fichas clínicas de los pacientes controlados del policlínico de Neuropediatría del Hospital de Puerto Montt, con cariograma anormal entre los años 2007 y 2012. De 248 pacientes, 12% se identificó una alteración; 58% aberraciones estructurales, 20% aneuploidías, y 20% alteraciones genético - moleculares. Los elementos clínicos que se encontraron fueron microcefalia 48%, retraso mental 67%, historia familiar 67%, hipotonía 70%, convulsiones 41%, alteraciones del SNC 37%.

Cytogenetic examination is an important tool for confirming diagnosis, case management and genetic counseling. The aim is to analyze the characteristics of neurobehavioral phenotypes, formalize and guide the effective application of cytogenetics. The medical records of patients with abnormal karyotype seen between 2007 and 2012 at the Hospital of Puerto Montt's neuropaediatric outpatient clinic were reviewed. Of 248 patients, in 12% an alteration was identified; 58% structural aberrations, 20% aneuploidy, and 20% genetic-molecular alterations. The clinical elements found were 48% microcephaly, 67% mental retardation, 67% family history, 70% hypotonia, 41% seizures, 37% CNS disorders.

simplified schematic design for cytogenetic testing strategies

The development of new genetic diagnostic, and hence therapeutic possibilities, has brought the realization that genetic disease is now an integral part of medical practice. Advances in cytogenetic and molecular testing have drastically improved the ability to diagnose with certainty many previously unrecognized genetic diseases. However, this advance in technology does not come without new questions. New tests are not always the most cost-effective ones and some have significant diagnostic limitations. Genetic tests fall under three major categories: chromosomal genetic tests; molecular genetic tests [DNA and gene tests]; and biochemical genetic tests [measuring the amount and activity of proteins]. This review article focuses on chromosomal anomalies and cytogenetic tests. The different types of cytogenetic tests, their indications, and the advantages and disadvantages of each of them are discussed. This review will also present the strategy of choice for each one of these tests depending on the type of chromosomal anomalies that we are searching for and the available specimen for diagnosis. Chromosomal anomalies represent one of the entities of genetic diseases. A large number of cytogenetic tests exist for diagnosis of these chromosomal anomalies. However, the choice of cytogenetic test to be carried out should be based on clinical indications, on the type and size of cytogenetic anomaly that we are searching for, and on the available specimen for diagnosis