Introducción: El aumento del número de repeticiones del triplete citosina-guanina-guanina (CGG), en el gen FMR1 es responsable de 3 síndromes OMIM con fenotipo clínico bien diferenciado: síndrome de X frágil (SXF) y 2 enfermedades en adultos portadores de la premutación (55-200 repeticiones CGG): insuficiencia ovárica primaria (FXPOI) y síndrome de temblor-ataxia (FXTAS) asociado al SXF. Observación clínica o métodos: Se estudió la mutación dinámica CGG del gen FMR1 en muestras de ADN de sangre periférica del caso índice y familiares de primer, segundo y tercer grado mediante TP-PCR, así como el porcentaje de metilación. Resultados: Se confirmó el diagnóstico del SXF en 3 pacientes (21,4%), 8 pacientes (57,1%) se encontraban en el rango de premutación, un paciente varón con mosaicismo premutación-mutación completa (7,1%) y 2 pacientes (14,3%) con estudio normal. De los 8 pacientes premutados, 3 presentaron FXPOI y un paciente varón FXTAS. Discusión: Nuestro estudio muestra la importancia de realizar un diagnóstico precoz del SXF y su consecuente estudio familiar y consejo genético, que permita identificar nuevos pacientes afectos o pacientes premutados con síndromes relacionados con el gen FMR1 (FXTAS, FXPOI) (AU)
Introduction: The dynamic increase in the number of triplet repeats of cytosine-guanine-guanine (CGG) in the FMR1gene mutation is responsible for three OMIM syndromes with a distinct clinical phenotype: Fragile X syndrome (FXS) and two pathologies in adult carriers of the premutation (55-200 CGG repeats): Primary ovarian insufficiency (FXPOI) and tremor-ataxia syndrome (FXTAS) associated with FXS. Clinical observation and methods: CGG mutation dynamics of the FMR1 gene were studied in DNA samples from peripheral blood from the index case and other relatives of first, second and third degree by TP-PCR, and the percentage methylation. Results: Diagnosis of FXS was confirmed in three patients (21.4%), eight patients (57.1%) were confirmed in the premutation range transmitters, one male patient with full mutation/permutation mosaicism (7.1%) and two patients (14.3%) with normal study. Of the eight permutated patients, three had FXPOI and one male patient had FXTAS. Discussion: Our study suggests the importance of making an early diagnosis of SXF in order to carry out a family study and genetic counselling, which allow the identification of new cases or premutated patients with FMR1 gene- associated syndromes (FXTAS, FXPOI) (AU)
Humans , Male , Female , Child, Preschool , Child , Adolescent , Young Adult , Adult , Middle Aged , Aged , Fragile X Syndrome/diagnosis , Fragile X Syndrome/genetics , Trinucleotide Repeat Expansion/physiology , Menopause, Premature , Intellectual Disability/diagnosis , Intellectual Disability/etiology , Primary Ovarian Insufficiency/diagnosis , Polymerase Chain Reaction/methods
INTRODUCTION: The dynamic increase in the number of triplet repeats of cytosine-guanine-guanine (CGG) in the FMR1 gene mutation is responsible for three OMIM syndromes with a distinct clinical phenotype: Fragile X syndrome (FXS) and two pathologies in adult carriers of the premutation (55-200 CGG repeats): Primary ovarian insufficiency (FXPOI) and tremor-ataxia syndrome (FXTAS) associated with FXS. CLINICAL OBSERVATION AND METHODS: CGG mutation dynamics of the FMR1 gene were studied in DNA samples from peripheral blood from the index case and other relatives of first, second and third degree by TP-PCR, and the percentage methylation. RESULTS: Diagnosis of FXS was confirmed in three patients (21.4%), eight patients (57.1%) were confirmed in the premutation range transmitters, one male patient with full mutation/permutation mosaicism (7.1%) and two patients (14.3%) with normal study. Of the eight permutated patients, three had FXPOI and one male patient had FXTAS. DISCUSSION: Our study suggests the importance of making an early diagnosis of SXF in order to carry out a family study and genetic counselling, which allow the identification of new cases or premutated patients with FMR1 gene- associated syndromes (FXTAS, FXPOI).
Ataxia/genetics , Fragile X Mental Retardation Protein/genetics , Fragile X Syndrome/genetics , Primary Ovarian Insufficiency/genetics , Tremor/genetics , Trinucleotide Repeats , Adolescent , Adult , Aged , Ataxia/diagnosis , Child , Child, Preschool , Female , Fragile X Syndrome/diagnosis , Genetic Markers , Genetic Testing , Humans , Male , Middle Aged , Mutation , Primary Ovarian Insufficiency/diagnosis , Tremor/diagnosis
