[Identifying deletions in the dystrophin gene and detecting carriers in families with Duchenne's/Becker's muscular dystrophy]. / Identificación de deleciones en el gen de la distrofina y detección de portadoras en familias con distrofia muscular de Duchenne/Becker.

INTRODUCTION: Between 60 and 65% of the mutations that cause Duchenne's/Becker's muscular dystrophy (DMD/BMD) are deletions in the dystrophin gene. Identifying deletions confirms the diagnosis and allows carriers to be detected with precision, which is the main preventive resource. The frequency and distribution of deletions in the DMD gene is unknown in south-east Mexico. AIMS: To identify deletions in the DMD gene and to detect carriers in families with DMD/BMD in south-east Mexico. PATIENTS AND METHODS: The study involved 26 families that showed clinical signs of DMD/BMD: Deletions were determined in the DNA of 40 males by means of the multiple polymerase chain reaction (PCR) in 22 segments of the gene. Detection of carriers was applied to 33 female relatives using PCR-restriction fragment length polymorphism of the polymorphic markers Pert 87.8/Taq 1, pERT 87.15/Bam H1, and single PCR for VNTR MP1P by linkage analysis. RESULTS: Deletions were identified in 67.5% of patients with DMD and they were located in the 5' end and in the central region, exons 44 to 52, of the gene. In the detection of carriers, 73.33% of the families were informative. The markers 87.8/Taq 1 and MPIP yielded the greatest information power, with 26.67 and 33.33%, respectively. Of a total of 33 females, 21 (63.64%) were carriers, one (3.03%) was a non-carrier and 11 (33.33%) were not informative. CONCLUSIONS: The frequency of deletions was 67.5%. Carrier status was determined in 66.67% of the females who were analysed. The markers pERT 87.8/Taq 1 and MP1P yielded the greatest information power.

Identificación de deleciones en el gen de la distrofina y detección de portadoras en familias con distrofia muscular de Duchenne/Becker / Identifying deletions in the dystrophin gene and detecting carriers in families with duchenne's/becker's muscular dystrophy

Introducción. Del 60 al 65% de las mutaciones que causan distrofia muscular de Duchenne/Becker (DMD/DMB)corresponden a deleciones en el gen de la distrofina. La identificación de deleciones confirma el diagnóstico y permite la detección precisa de portadoras, que es el recurso principal de prevención. En el sudeste de México se desconoce la frecuencia y distribución de las deleciones del gen DMD. Objetivos. Identificar deleciones del gen DMD y detectar portadoras en familiascon DMD/DMB del sudeste de México. Pacientes y métodos. Se incluyeron 26 familias cuyo propósito mostró signos clínicos de DMD/DMB. Las deleciones se determinaron en el ADN de 40 varones mediante reacción en cadena de la polimerasa (PCR) múltiple de 22 segmentos del gen. La detección de portadoras se aplicó a 33 familiares femeninos con PCR mediante polimorfismo de longitud de fragmentos de restricción de los marcadores Pert 87.8/Taq 1, pERT 87.15/Bam H1, y PCR simplepara el VNTR MPIP mediante análisis de ligamiento. Resultados. Las deleciones se identificaron en el 67,5% de pacientes con DMD y se localizaron en el extremo 5’ y en la región central, exones 44 al 52, del gen. En la detección de portadoras, el 73,33% de las familias resultó informativo. Los marcadores 87.8/Taq I y MPIP arrojaron el mayor poder de información, con el 26,67 y el 33,33%, respectivamente. De 33 mujeres, 21 (63,64%) resultaron portadoras, una (3,03%) no portadora y 11 (33.33%) no fueron informativas. Conclusión. La frecuencia de deleciones fue del 67,5%. Se determinó el estado de portador en el 66,67% de las mujeres analizadas. Los marcadores pERT 87.8/Taq 1 y MPIP arrojaron el mayor poder de información

Introduction. Between 60 and 65% of the mutations that cause Duchenne’s/Becker’s muscular dystrophy (DMD/BMD)are deletions in the dystrophin gene. Identifying deletions confirms the diagnosis and allows carriers to be detected with precision, which is the main preventive resource. The frequency and distribution of deletions in the DMD gene is unknown in south-east Mexico. Aims. To identify deletions in the DMD gene and to detect carriers in families with DMD/BMD in south-eastMexico. Patients and methods. The study involved 26 families that showed clinical signs of DMD/BMD. Deletions were determined in the DNA of 40 males by means of the multiple polymerase chain reaction (PCR) in 22 segments of the gene. Detection of carriers was applied to 33 female relatives using PCR-restriction fragment length polymorphism of the polymorphicmarkers Pert 87.8/Taq 1, pERT 87.15/Bam H1, and single PCR for VNTR MP1P by linkage analysis. Results. Deletionswere identified in 67.5% of patients with DMD and they were located in the 5’ end and in the central region, exons 44 to 52, of the gene. In the detection of carriers, 73.33% of the families were informative. The markers 87.8/Taq 1 and MPIP yielded thegreatest information power, with 26.67 and 33.33%, respectively. Of a total of 33 females, 21 (63.64%) were carriers, one (3.03%) was a non-carrier and 11 (33.33%) were not informative. Conclusions. The frequency of deletions was 67.5%. Carrier status was determined in 66.67% of the females who were analysed. The markers pERT 87.8/Taq 1 and MP1P yielded the greatest information power