Who Carries The Gene For Muscular Dystrophy?

Muscular dystrophy (MD) is a genetic disease which runs in families. It is characterized by progressive degeneration and weakness of muscles of the body due to deficiency of a protein named dystrophin.1 The genes that carry instructions for the production of this protein are defective in the patients with muscular dystrophy. The defective gene is inherited from either one or both the parents who act as a carrier of these genes. The mutated genes lead to the impairment of the structure and function of the muscles. The patients with muscular dystrophy have problems relating walking, gait, and swallowing and muscle coordination.

Who Carries The Gene For Muscular Dystrophy?

Muscular dystrophy is a set of more than 30 genetic disorders that lead to the gradual and progressive wasting and weakness of the muscles.2 This happens due to the passage of defective genes from one or both the parents who usually carry them. The patient with muscular dystrophy feels problems with the movement of the extremities and tongue.

The inheritance of the genes can be understood by its specific types. These types of disorders are-

Recessive Inherited Disorder

In this condition, the child gets a mutated gene from one of the parents and becomes the carrier of the disease, but does not have the disease. This means his children may get the defective genes from him if his partner also carries the defective genes. This is mostly seen in limb-girdle muscular dystrophy.

If both the parents carry the defective gene that causes muscular dystrophy, then, there is a-

  • 25% chances that their child will suffer from muscular dystrophy.
  • 25% chances that the child acts as a carrier of the mutated gene from his mother
  • 25% chances that the child acts as a carrier of the mutated gene from his father
  • 25% chances that they will not inherit the genes and will lead a healthy life

Dominant Inherited Disorder

In this condition, the patient will inherit the defective genes from one of the parents who actually have muscular dystrophy. If the patient and his unaffected partner have children, then there are 50% chances that these children will develop the condition. This type of disorder is inherited in facioscapulohumeral Muscular dystrophy, myotonic Muscular dystrophy, oculopharyngeal Muscular dystrophy and some variations of limb-girdle Muscular dystrophy.

Sex-Linked (X-Linked Disorder)

Male and female have a set of XY and XX chromosomes which determine their sex. Sex-linked disorder of muscular dystrophy is passed from generation to generation due to a mutation in X chromosomes. If the mutation has developed in the X chromosome of males, then there is a chance the one copy of this defective gene may pass to their sons. Females have fewer chances to develop this condition as both X chromosomes should have defective genes. If the defective gene is passed from the father only, then female do not develop muscular dystrophy. The disorder is also not so severe in females as it is seen in the males. This type of muscular dystrophy is found in Duchenne muscular dystrophy and Becker muscular dystrophy. This is the reason why this type of muscular dystrophy is more common and more severe ones in males.

Spontaneous gene mutations happen in some individuals due to which they can develop muscular dystrophy even though they do not have a family history. These mutations have no reason to occur and affect the function of the cells of muscles.

Even the family history is not present in some persons; they can still develop muscular dystrophy. The main reason behind this is the mutated genes are inherited in both sides of the family from generation to generation but nobody develops the condition.

Conclusion

Muscular dystrophy is a disease of muscles which is inherited from one or both the parents. This disease is caused due to the passing of mutated or defective genes from one person to another in a family. one or both the parents can carry the gene of muscular dystrophy.

References:  

Also Read: