Dystrophinopathy / 中华神经科杂志

Dystrophinopathy is a group of inherited diseases caused by the defect of dystrophin protein with X-linked recessive inheritance.The disease is clinically characterized by progressive severe muscles weakness and atrophy of proximal limb muscles and belt muscle,gastrocnemius pseudohypertrophy.The patient lose the ability of daily exercise,and ultimately succumb to restrictive lung disease or cardiac death.According to the clinical manifestations and the defect degree of dystrophin protein,dystrophinopathy is divided into:Duchenne muscular dystrophy (DMD),Becker muscular dystrophy,X-linked dilated cardiomyopathy,and female carrier of DMD.Patients can present with multi-system involvement at different stages of the disease,which require multidisciplinary management to alleviate symptoms,prolong life and improve quality of life.Glucocorticoids can significantly extend the independent activity of children by 2-5 years.Due to the high incidence,poor quality of life in the early stage and high disability and lethality in the late stage,it is important to strengthen the understanding of neurologists about this disease and conduct early diagnosis,full management and genetic counseling.

Magnetic resonance imaging of dystrophinopathy that mimics adductor enthesopathy / 北京大学学报(医学版)

Objective:To report thigh muscle magnetic resonance imaging (MRI)tests of four Chinese patients with dystrophinopathy with edema changes in adductor longus muscles that mimics adductor en-thesopathy.Methods:Four boys,who were from four unrelated families and aged from 5 to 11 years, were investigated because of the clinical manifestations including myalgia or muscle weakness or the inci-dental findings of elevated serum creatine kinase levels,and were diagnosed with dystrophinopathy by gene test of Duchenne muscular dystrophy (DMD).Their creatine kinase levels were increased from 4 087 IU /L to 32 700 IU /L (Normal range:75 -175 IU /L).The muscle biopsy of three patients all demonstrated a dystrophic pattern including necrosis,regeneration,hypertrophy,atrophy and connective tissue proliferation,with different proportions of dystrophin-negative muscle fibers.The gene test of DMD showed an out-frame deletion of exons in three of the four patients,involving either exons 45 or exons 49 -52 deletion or exon 62 duplication,and c.2665 C >T with nonsense mutation in the other one. Muscle MRI tests of the bilateral thighs were performed with T1 weighed sequence and slow tau inversion recovery sequence.The degree of fatty infiltration changes was scored.Results:MRI of the thigh mus-cles showed mild to severe fatty infiltration changes in T1 weighed sequence with the total scores from 2 to 13.The most severe fatty infiltration changes were in the long head of biceps femoris and adductor mag-nus.Obvious hyperintensities appeared mainly in the adductor longus muscles on slow tau inversion re-covery (STIR)images in all the patients without any abnormal signals in the attachment of the ligament, indicating edema changes of the adductor longus muscles which mimiced adductor enthesopathy.Two of the four patients presented with edema changes in the bilateral adductor longus muscles,while the other two were with only unilateral changes.Furthermore,other thigh muscles,including adductor magnus, semitendinosus,sartorius and rectus femoris muscles,could also have mild edema changes in two of the four patients.Conclusion:Dystrophinopathy can manifest as edema changes in the adductor longus mus-cles in thigh muscle MRI tests,which is a typical lesion in adductor enthesopathy.The adductor longus muscles in the dystrophinopathy patients may be easy to be impaired due to traction injury during sports.

Clinical and Genetic Characterization of Female Dystrophinopathy

BACKGROUND AND PURPOSE: Duchenne and Becker muscular dystrophies are the most common X-linked recessive muscular dystrophies. Dystrophin gene mutations usually affect men, but reportedly 2.5-7.8% of women are affected and are classified as symptomatic carriers. The aim of this study was to clinically and genetically characterize symptomatic female dystrophinopathy carriers. METHODS: The clinical and genetic data of 11 female dystrophinopathy carriers among 285 patients who underwent multiplex ligation-dependent probe amplification (MLPA) analysis for the dystrophin gene were reviewed. Women with muscle weakness and/or dilated cardiomyopathy were classified as symptomatic carriers, while subjects with high serum creatine kinase (CK) levels and/or minor myopathic signs such as muscle cramps and myalgia were classified as asymptomatic. RESULTS: Twelve female carriers were identified, but 1 symptomatic carrier who also had Turner syndrome was excluded from the study. Of the 11 included female carriers, 4 were symptomatic and 7 were asymptomatic. The age at symptom onset in the symptomatic female carriers ranged from 15 to 31 years (mean, 30.6 years), and the age at diagnosis for asymptomatic carriers ranged from 4 to 38 years (mean, 24.5 years). Serum CK levels were markedly elevated (mean, 1,301 IU/mL) in three of the four (75%) symptomatic female carriers, and mildly elevated in three of the seven (42%) asymptomatic female carriers. Symptomatic female carriers typically presented with asymmetric bilateral leg weakness as the initial symptom, with aggravated symptoms after labor. CONCLUSIONS: Female dystrophinopathy is not uncommon, and it is an important factor with respect to males with dystrophinopathy who may be born to such patients. Screening with MLPA is useful because it can aid in early diagnosis and appropriate management.

Female Carriers of Duchenne Muscular Dystrophy

Dystrophinopathy, caused by mutations in the DMD gene, presents with variable clinical phenotypes ranging from the severe Duchenne muscular dystrophy (DMD) to the milder Becker muscular dystrophy(BMD) forms. DMD is a recessive X-linked form of muscular dystrophy. Two-thirds of mothers of affected males are thought to be DMD carriers. Approximately 2.5-7.8% of female DMD carriers have muscle weakness and are categorized as manifesting DMD carriers. The symptoms of female carriers of DMD range from mild muscle weakness to severe gait problems. The most commonly presented symptom is mild proximal muscle weakness, which is often asymmetric and progressive, but shows variable clinical spectrum with BMD of more severe DMD-like phenotype. Atypical presentations in manifesting carriers are myalgia or cramps without limb weakness, isolated cardiomyopathy and camptocormia. Multiplex PCR and MLPA analysis are common techniques to identify mutations in the DMD gene. Relationship between X-chromosome inactivation and clinical severity is not clear. Female carriers of DMD are not less common, and they have an important role of birth of a male DMD.

Three Cases of Manifesting Female Carriers in Patients with Duchenne Muscular Dystrophy

Duchenne muscular dystrophy usually affects males. However, females are also affected in rare instances. Approximately 8% of female Duchenne muscular dystrophy (DMD) carriers are manifesting carriers and have muscle weakness to some extent. We investigated the clinical features of 3 female patients with dystrophinopathy diagnosed by clinical, pathological, and genetic studies at our neuromuscular disease clinic. The onset age of manifesting symptoms varied (8-28 years). Muscle weakness grade varied as follows: patient 1 showed asymmetrical bilateral proximal upper and lower extremities weakness, patient 2 showed asymmetrical bilateral upper extremities weakness similar to scapulohumoral muscular dystrophy, and patient 3 had only bilateral asymmetric proximal lower extremities weakness. Two patients had familial histories of DMD (their sons were diagnosed with DMD), but the 1 remaining patient had no familial history of DMD. The serum creatine kinase level was elevated in all patients, but it was not correlated with muscular weakness. An electromyography study showed findings of myopathy in all patients. One patient was diagnosed with a DMD carrier by a muscle biopsy with an immunohistochemical stain (dystrophin). The remaining 2 patients with familial history of DMD were diagnosed by multiplex ligation-dependent probe amplification (MLPA). There were inconsistent clinical features in the female carriers. An immunohistochemical analysis of dystrophin could be useful for female carrier patients. Also, multiplex ligation-dependent probe amplification is essential for the diagnosis of a manifesting female carrier DMD in female myopathic patients because conventional multiplex PCR could not detect the duplication and is less accurate compared to MLPA.

Three Cases of Manifesting Female Carriers in Patients with Duchenne Muscular Dystrophy

Duchenne muscular dystrophy usually affects males. However, females are also affected in rare instances. Approximately 8% of female Duchenne muscular dystrophy (DMD) carriers are manifesting carriers and have muscle weakness to some extent. We investigated the clinical features of 3 female patients with dystrophinopathy diagnosed by clinical, pathological, and genetic studies at our neuromuscular disease clinic. The onset age of manifesting symptoms varied (8-28 years). Muscle weakness grade varied as follows: patient 1 showed asymmetrical bilateral proximal upper and lower extremities weakness, patient 2 showed asymmetrical bilateral upper extremities weakness similar to scapulohumoral muscular dystrophy, and patient 3 had only bilateral asymmetric proximal lower extremities weakness. Two patients had familial histories of DMD (their sons were diagnosed with DMD), but the 1 remaining patient had no familial history of DMD. The serum creatine kinase level was elevated in all patients, but it was not correlated with muscular weakness. An electromyography study showed findings of myopathy in all patients. One patient was diagnosed with a DMD carrier by a muscle biopsy with an immunohistochemical stain (dystrophin). The remaining 2 patients with familial history of DMD were diagnosed by multiplex ligation-dependent probe amplification (MLPA). There were inconsistent clinical features in the female carriers. An immunohistochemical analysis of dystrophin could be useful for female carrier patients. Also, multiplex ligation-dependent probe amplification is essential for the diagnosis of a manifesting female carrier DMD in female myopathic patients because conventional multiplex PCR could not detect the duplication and is less accurate compared to MLPA.