10) Hereditary Muscle Disorders

What is the most basic cause of hereditary skeletal muscle disorders?

Defects in genes affecting muscle structure or function

Which inheritance pattern is associated with Duchenne muscular dystrophy?

X-linked recessive

Which protein is absent in Duchenne muscular dystrophy?

Dystrophin

What tissue replaces muscle in advanced stages of Duchenne muscular dystrophy?

Fibrous and fatty tissue

What visual symptom is commonly seen in Duchenne muscular dystrophy affecting the calves?

Pseudohypertrophy from tissue replacement

Becker’s muscular dystrophy is considered less severe than Duchenne because:

It results in reduced rather than absent dystrophin

Which of the following is NOT a typical pathological mechanism in muscular dystrophies?

Autoimmune targeting of nerve endings

What structural abnormality is associated with congenital myopathies?

Rod-like inclusions and cores

Which histological subtype is NOT part of congenital myopathies classification?

Sarcomeric sclerosis

Which fibres are predominant in congenital myopathies?

Type I fibres showing hypertrophy

Myotonia congenita primarily involves mutations in:

Skeletal muscle chloride channels

Myotonia results in:

Difficulty in relaxing contracted muscles

Which fibre type is hypertrophied in myotonia on biopsy?

Type II fibres

Which histological feature is typical of myotonia?

Increased endomysial connective tissue

Which of the following best describes glycogen storage disease effects on muscles?

Basophilic glycogen vacuole accumulation

Lipid storage diseases cause:

Abnormal lipid accumulation and increased lipid droplets

Which muscle fibre type shows more lipid droplets in lipid storage diseases?

Type I slow-twitch oxidative