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The gold standard diagnostic test for Ullrich congenital muscular dystrophy (UCMD) is molecular testing for COL6 mutation. The facility for genetic testing is sparingly available and it is usually diagnosed by muscle biopsy. The latter is an invasive procedure requiring expertise and sedation. Skin biopsy has shown promise as a simpler diagnostic modality. Eleven and 7 cases, respectively, of phenotypically suspected Ullrich congenital muscular dystrophy and dystrophinopathy underwent simultaneous skin and muscle biopsies, which were subjected to hematoxylin and eosin (H&E) and immunohistochemistry staining for collagen VI and dystrophin 1, 2, and 3. Of the 8 and 5 muscle biopsy–confirmed cases of Ullrich congenital muscular dystrophy and dystrophinopathy, 6 Ullrich congenital muscular dystrophy and 5 dystrophinopathy cases showed absent and preserved COL6 staining, respectively, in the skin biopsy. Skin biopsy as a diagnostic option has shown encouraging results in Ullrich congenital muscular dystrophy. These should be evaluated in larger studies. [ABSTRACT FROM AUTHOR]

Dystrophinopathies are diagnosed by genetic studies and muscle biopsy. Most centers have multiplex polymerase chain reaction facilities diagnosing 65% to 70% of dystrophinopathy cases. Muscle biopsy is a time-consuming, invasive procedure whereas skin biopsy is a simple procedure done under local anesthesia. The current study evaluated the diagnostic accuracy of skin biopsy in dystrophinopathy. Overall, 119 confirmed cases of muscular dystrophy (111 males and 8 females) were included in the final analysis, of which 100 (all males) were dystrophinopathy. Skin biopsy diagnosed dystrophinopathy in suspected muscular dystrophy patients with a sensitivity of 98% (92.3%-99.7%), specificity of 99% (93.7%-99.9%), positive predictive value of 94.7% (71.9%-99.7%), and negative predictive value of 90% (66.9%-98.2%). Skin biopsy can be used for screening dystrophinopathy in muscular dystrophy patients (high sensitivity and positive predictive value). It being a simple and minimally invasive procedure, histopathologic and molecular markers of disease progression and response to novel treatment options can be assessed serially. [ABSTRACT FROM PUBLISHER]

A 10-year-old girl presented with progressive proximal limb muscle weakness without facial, ocular, or bulbar muscle involvement. There was no fatigability or diurnal fluctuation in symptoms. Her weakness worsened with febrile illnesses and recovered with accruing disabilities over a few weeks. Serum creatine kinase levels and muscle biopsy were normal. A significant decrement on repetitive nerve stimulation test and positive response to therapeutic neostigmine challenge test confirmed the diagnosis of limb-girdle myasthenia. She responded well to corticosteroids and thymectomy, demonstrating a likely autoimmune etiology. This case highlights the long-term fluctuations in a case of myasthenia gravis and the need for a high index of suspicion for myasthenia in children presenting with unexplained muscle weakness, even in the absence of typical features such as fatigability, diurnal fluctuation, and oculobulbar weakness. [ABSTRACT FROM PUBLISHER]

Muscular dystrophies are progressive, genetic disorders of muscle degeneration. The current gold standard for diagnosis is muscle biopsy or genetic studies. Muscle biopsy is an invasive procedure and genetic testing facilities are available only in a few centers. Thus, a diagnostic test that is easily available, simpler, and less invasive is desirable. Over the past 2 decades, skin biopsy has been evolving as a suitable option. Two cases of sarcoglycanopathy are described here, which have been correctly diagnosed by skin biopsy. Muscle biopsy has been used as the gold-standard diagnostic method. Skin biopsy can substitute for muscle biopsy as the preliminary diagnostic tool directing appropriate molecular testing. However, these results require validation in studies with an adequate sample size. This holds promise for the future when repeated biopsies will be required for evaluating protein rescue in trials of novel treatment options in these disorders. [ABSTRACT FROM AUTHOR]