Qualitative or quantitative defects of dystrophin
- Synonyms
- Dystrophinopathies
Summary
Excerpted from the GeneReview:The dystrophinopathies cover a spectrum of X-linked muscle disease ranging from mild to severe that includes Duchenne muscular dystrophy, Becker muscular dystrophy, and DMD-associated dilated cardiomyopathy (DCM). The mild end of the spectrum includes the phenotypes of asymptomatic increase in serum concentration of creatine phosphokinase (CK) and muscle cramps with myoglobinuria. The severe end of the spectrum includes progressive muscle diseases that are classified as Duchenne/Becker muscular dystrophy when skeletal muscle is primarily affected and as DMD-associated DCM when the heart is primarily affected. Duchenne muscular dystrophy (DMD) usually presents in early childhood with delayed motor milestones including delays in walking independently and standing up from a supine position. Proximal weakness causes a waddling gait and difficulty climbing stairs, running, jumping, and standing up from a squatting position. DMD is rapidly progressive, with affected children being wheelchair dependent by age 12 years. Cardiomyopathy occurs in almost all individuals with DMD after age 18 years. Few survive beyond the third decade, with respiratory complications and progressive cardiomyopathy being common causes of death. Becker muscular dystrophy (BMD) is characterized by later-onset skeletal muscle weakness. With improved diagnostic techniques, it has been recognized that the mild end of the spectrum includes men with onset of symptoms after age 30 years who remain ambulatory even into their 60s. Despite the milder skeletal muscle involvement, heart failure from DCM is a common cause of morbidity and the most common cause of death in BMD. Mean age of death is in the mid-40s. DMD-associated DCM is characterized by left ventricular dilatation and congestive heart failure. Females heterozygous for a DMD pathogenic variant are at increased risk for DCM.
- Full text of GeneReview (by section):
- Summary
- GeneReview Scope
- Diagnosis
- Clinical Characteristics
- Genetically Related (Allelic) Disorders
- Differential Diagnosis
- Management
- Genetic Counseling
- Resources
- Molecular Genetics
- Chapter Notes
- References
- Authors:
- Basil T Darras
- David K Urion
- Partha S Ghosh
- view full author information
Available tests
31 tests are in the database for this condition.
Check Related conditions for additional relevant tests.
- ACMG Algorithm, 2022American College of Medical Genetics and Genomics, Algorithm, ELEVATED CREATINEKINASE(CK)-MM , Genetic Neuromuscular Disorders, 2022
- ACMG ACT, 2020American College of Medical Genetics and Genomics, Newborn Screening ACT Sheet, Elevated creatine kinase muscle isoform (CKMM), Genetic Neuromuscular Disease, 2020
- ACMG ACT, 2019American College of Medical Genetics and Genomics, Newborn Screening ACT Sheet, Pathogenic Variant in Dystrophin (DMD Gene) and elevated creatine kinase muscle isoform (CK-MM), Duchenne and Becker Muscular Dystrophy, 2019
IMPORTANT NOTE: NIH does not independently verify information submitted to the GTR; it relies on submitters to provide information that is accurate and not misleading. NIH makes no endorsements of tests or laboratories listed in the GTR. GTR is not a substitute for medical advice. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.