Down Syndrome and Fragile X Syndrome in a Colombian Woman: Case Report.

BACKGROUND: Down syndrome (DS) and Fragile X syndrome (FXS) are the major genetic causes of intellectual disabilities. Here, we present a case of a 32-year-old woman with the diagnosis of both FXS and DS. She is the daughter of a 47-year-old pre-mutation woman who also has three sons with FXS. METHODS: Cytogenetic testing detected the presence of a complete trisomy 21. A combination of PCR and Southern blot analysis was utilized to document the presence of the FMR1 full mutation. RESULTS: The patient has physical characteristics and behavioural disturbances typical of both FXS and DS, which were confirmed by molecular testing. Her treatment plan included a trial of sertraline because of the severity of her shyness and lack of language. She had an excellent response to sertraline with improvement in shyness and social interactions, particularly with family members. CONCLUSIONS: In this study, we report the case of a woman with both FXS and DS, which is the fifth case of FXS and DS in the world's literature. The patient is from Ricaurte, a small town in Colombia, South America, where there is the world's highest prevalence for FXS.

Variedad de la presentación citogenética en el síndrome de turner, prenatal y postnatal / Cytogenetics variety of presentation turner syndrome, prenatal and postnatal

Antecedentes: El síndrome de Turner (ST) es causado por la ausencia total o parcial del cromosoma X y posee una gran variedad en su presentación citogenética. Objetivos: Determinar la variedad de presentación citogenética y la existencia de diferencias entre los casos diagnosticados in útero y los de diagnóstico postnatal, en pacientes con ST en dos laboratorios de referencia de Cali, Colombia. Métodos: Se realizó un estudio observacional descriptivo de corte transversal, se incluyeron pacientes con diagnóstico de ST, cuyo cariotipo se realizó entre los años 2000 y 2012, en los laboratorios de citogenética de la Universidad del Valle y un instituto de genética de Cali, Colombia. Se recolectó información del reporte del cariotipo, tipo de muestra y tiempo de realización del diagnóstico y se determinó frecuencias y asociaciones estadísticas entre las variables a estudiar. Resultados: Se incluyeron 181 pacientes con fórmula cromosómica compatible con ST; 69 fueron diagnosticados in útero, los demás, en recién nacidos vivos, infantes o adultos. La fórmula cromosómica 45 X0 se encontró en el 95,6 por ciento de los casos de diagnóstico prenatal y 58 por ciento de los de diagnóstico postnatal. Se aplicó la prueba del test exacto de Fisher, comparando los múltiples subgrupos de la variedad de presentación citogenética de diagnóstico prenatal y postnatal, encontrándose diferencias estadísticamente significativas en la distribución de las dos poblaciones evaluadas (p<0,001). Conclusiones: Existen diferencias significativas en los cariotipos de los pacientes con ST diagnosticados in útero, respecto a los diagnosticados en vida extrauterina. Se postula que esa diferencia tendría una explicación biológica sobre la posibilidad de muerte in útero por la ausencia total del cromosoma X.

Background: Turner syndrome is caused by the complete or partial absence of chromosome X and has a great variety in their cytogenetic presentation. Objectives: To determine the variety of cytogenetic presentation and the presence of differences between cases diagnosed in uterus and postnatally, in patients with Turner syndrome at two reference laboratories of Cali, Colombia. Methods: A descriptive cross-sectional study was performed. We included patients with cytogenetic diagnosis of Turner syndrome performed between 2000 and 2012 at cytogenetic laboratories of Universidad del Valle and a genetic institute in Cali, Colombia. The information of karyotype result, type of sample and the diagnosis moment was collected, determining frequencies and statistical associations. Results: 181 patients with Turner's chromosomic presentation; 69 were diagnosed in uterus, the other as live newborns, infants or adults. Chromosomal formula 45X0 was found in 95.6 percent of cases with prenatal diagnosis and 58 percent of postnatal diagnosis. Fisher's test was applied, comparing the cytogenetic presentations of prenatal and postnatal diagnosis, statistically significant difference in the distribution of the two populations evaluated was found (p<0.001). Conclusions: There are significant differences in the karyotypes of patients with ST diagnosed in utero, compared to those diagnosed in postnatal life. We hypothesize that this difference would have a biological explanation due to a higher probability of death in utero by the complete absence of chromosome X.