Duchenne Muscular Dystrophy Overview

Questions and Answers

What is the most likely diagnosis for a 4-year-old boy who has a waddling gait and increasing difficulty rising from a sitting position?

Metabolic Myopathy

Duchenne Muscular Dystrophy (correct)

Spinal Muscular Atrophy

Cerebral Palsy

Which of the following statements accurately describes the genetic basis of Duchenne Muscular Dystrophy?

It is inherited in an autosomal dominant manner.

It is inherited as an X-linked recessive trait. (correct)

It affects only females due to its dominant inheritance.

It is a spontaneous mutation with no family history.

What is the mechanism of disease underlying Duchenne Muscular Dystrophy?

Decreased muscle fiber regeneration

Absence of dystrophin protein (correct)

Overproduction of muscle proteins

Excessive mitochondrial activity

What are the obligatory criteria that distinguish muscular dystrophies from other neuromuscular diseases?

It is a primary myopathy with a genetic basis. Signup and view all the answers

Which statement regarding the clinical presentation of Duchenne Muscular Dystrophy is true?

Weakness in hip girdle muscles is often seen by age two. Signup and view all the answers

What is the incidence rate of Duchenne Muscular Dystrophy among liveborn infant boys?

1 in 3,600 Signup and view all the answers

What does the term 'dystrophy' indicate in the context of muscular dystrophies?

Abnormal growth and nourishment of muscle fibers Signup and view all the answers

Which clinical sign is most likely to be the initial indication of Duchenne Muscular Dystrophy in infancy?

Poor head control Signup and view all the answers

What percentage of normal dystrophin content is typically present in individuals with Duchenne Muscular Dystrophy?

0% to 5% Signup and view all the answers

Which feature is associated with muscle fiber degeneration in muscular dystrophies?

Progressive degeneration and death of muscle fibers Signup and view all the answers

Study Notes

Case Scenario

Concerns arise for a 4-year-old boy's walking ability; he started at 16 months and presents clumsiness and frequent falls.
Parents were previously reassured by a pediatrician that he would "outgrow" his clumsiness.
Child demonstrates a "waddling" gait and difficulty rising from the floor in the last month.

Possible Diagnosis

Likely diagnosis is a form of Muscular Dystrophy, specifically Duchenne Muscular Dystrophy (DMD).

Diagnostic Test

The diagnostic test of choice for Muscular Dystrophies is genetic testing, particularly to check for mutations in the dystrophin gene.

Mechanism of Disease

Muscular dystrophy involves abnormal muscle growth and degeneration, rooted in genetic mutations affecting muscle fiber function.
It is characterized by being a primary myopathy with a genetic basis, progressive course, and eventual degeneration of muscle fibers.

Duchenne Muscular Dystrophy (DMD)

DMD is the most prevalent hereditary neuromuscular disorder, affecting all racial and ethnic groups.
The incidence rate is approximately 1 in 3,600 liveborn infant boys.
Inherited via X-linked recessive trait, with the abnormal gene located at the Xp21 locus.
Dystrophin, a key structural protein, is markedly deficient in DMD, ranging from 0% to 5% of normal levels.

Clinical Presentation

Boys with DMD are usually asymptomatic at birth or in early infancy but may exhibit mild hypotonia.
Gross motor developments such as rolling over, sitting, and standing may occur on time or with slight delays.
Typically, children start walking around the age of 12 months, but hip girdle weakness can start subtly by the age of 2.
The first observable sign might be delayed head control during infancy.

Description

This quiz explores the clinical presentation and diagnosis of Duchenne Muscular Dystrophy (DMD) in pediatric patients. It covers key aspects including symptoms, genetic testing, and the disease mechanism. Test your understanding of this hereditary condition's implications for muscle function and development.