Introduction to Duchenne Muscular Dystrophy
What is Duchenne muscular dystrophy (DMD): Duchenne muscular dystrophy (DMD) is a disease that affects the development of muscles in children.
Causes: The human muscle is deficient in a protein called Dystrophin, which prevents the muscle cells from functioning normally and causes them to gradually die.
Symptoms.
1. In early childhood, there are more normal muscle cells, so the symptoms are not obvious.
2.At the age of three to four years, the child’s physical performance is poor.
3.At the age of five to six years old, the symptoms start to become obvious, with clinical manifestations such as
★ Once sitting on the floor, it is difficult to stand up and stand up in a special posture, i.e. Gao’s sign.
★ Difficulty in going up stairs and slopes.
★walking on a flat road in search of balance, with the stomach held forward and the upper body tilted back.
★ hypertrophy of the calf gastrocnemius muscle phenomenon.
★ scoliosis.
★ A few children with mental retardation.
Diagnostic methods.
1, enzymatic testing: creatine kinase (CK) is an enzyme that makes energy for muscle tissue, the concentration of CK in the blood of patients with DMD is much higher than normal, and the level is generally 10-100 times higher than normal.
2, electromyography: electromyography can usually find electrophysiological changes in muscle.
3, cellular immunochemical methods: through the electron microscope, the composition of muscle cell Dystrophin protein is directly observed, so as to diagnose DMD.
4, muscle tissue biopsy: under the microscope, the affected muscle tissue will be seen to vary in size, the number of muscle fibers is reduced, and the muscle fibers are filled with fibrous tissue in their place.
5, genetic examination: through the molecular biology method, detect the mutation of the corresponding genetic gene.
DMD trivia questions and answers
Q1: Can prenatal diagnosis detect DMD in fetus?
A: If there are DMD patients in the family, women need to do DMD gene testing before pregnancy to determine whether they are gene carriers. During pregnancy, the amniotic fluid of the pregnant woman will be taken for genetic analysis to know whether the fetus has the disease.
Q 2: What is the possibility of DMD being inherited?
A: DMD is a hereditary muscular dystrophy, and its gene is present on the X chromosome in humans, so DMD is inherited through a sexual chain. If a woman carries a mutated Dystrophin gene on one of her X chromosomes, she becomes a DMD carrier, so her son has a 50% chance of becoming a DMD patient, and her daughter has a 50% chance of becoming a DMD patient.
Since men have only one X chromosome, the vast majority of DMD patients are men; women have two X chromosomes, so even if one X chromosome is mutated, there is still a normal X chromosome to function, so women are more often DMD carriers and rarely develop the disease.