if you mean genetic muscolar myopathy there are entire Institutes working on this issue. Telethon funds with million of euros in europe the Research. I'm not working on it, but I'm overwhelmed with letters requesting donations for this issue.
The patients with benign type of muscular dystrophy (for example FSHD, distal forms, some form of limb-girdle MD as well as a congenital nyopathy with late onset) can work a very long time. However, the patients with Duchenne type MD cannot work because they have a severe weakness of pelvic girdle and shoulder girdle muscles which greatly disturbe their motor activity. For treatment pathient with muscular dystrophy (and myopathy) use CoQ10, idebenon (noben), L-carnitine, albutirol (salbutamol), cortocosteroid (deflazacort, prednisolon). There are a trial treatment by RTC 124, as well as a steam sells (the me insulin-like growth factor 1, inhibitors of proteas and myostatin as well as a steam cells (the mesoangioblasts) and exon skipping for Duchenne MD and limb-girdle MD.
http://Morgan J.E. Steam cells to treat muscular dystrophies. Acta Myol. 2005;24 (3): 181-183. Morosetti R. et al. Isolation and characterization of mesoangioblasts from facioscapulohumeral muscle biopsy. Steam Cells 2007; 25:3173-82. Sheuerbrandt G. Exon skipping with U7 gene transfer. Acta Myol. 2006;25: 40-42.Muntoni F. The development of antisence oligonucleotide therapies for Duchenne muscular dystrophy. Neuromuscul Disord. 2010; 20:355-62.
I think that the best place for diagnosis and treatment of muscle disease in children is the Dubowitz Neuromuscular Centre,UCL Institute of Child Health & Great Ormond Street Hospital for Children, London, United Kingdom
By definition, a myopathy is a disease of muscle.There are many different types. Some myopathies are inherited, some inflammatory, and some caused by endocrine problems. These are generally less severe than muscular dystrophy, an umbrella term for a group of degenerative muscle disorders involving very specific genetic mutations in different genes responsible for one of the proteins needed for normal muscle cell function. Some of these mutations are very rare--for example in the genes for desmin and alpha B-crystallin protein that lead to the so-called "Z-discopathies" or "desmin-related myopathies (DRM). Most of the active research going on, funded by the telethons mentioned in another reply, are for Duchenne's and Becker muscular dystrophy (presents in young boys only), spinal muscular atrophy, and various mitochondrial myopathies and forms of limb-girdle disorders (eg Miyoshi distal myopathy, calpainopathy). Most inherited muscle disorders are autosomal dominant. In some, moreover, even though family members share the exact same genotype, their phenotype is completely different, meaning it is not possible to project the age of onset, rate of progression, or the severity of the particular muscle pathology. Understand that -- as yet -- there are no cures and only a few palliative treatments mostly involving assistive technology to compensate for functional loss in muscle strength (eg, wheelchairs, ventilation apparatus, etc). To date,muscle diseases have been an underfunded area of research generally, but it's also been limited by the fact that technology is only now catching up to permit the hybrid use of approaches by molecular chemists and geneticists to rigorously identify properties of the proteostasis network and pathways using NMR and mass spectometry and electronmicrosopy. Without understanding certain protein-protein interactions occurring in muscle cells, they can't identify targets for developing drugs that will prevent disease onset. I'm sorry about your family members but would suggest they get sequenced to identify the mutant genes involved to get a better handle on which myopathy they have.
A brief postscript. Researchers at the Department of Pathology, All India Institute of Medical Sciences, New Delhi, India, have published in this area -- especially Dr. Mehar C Sharma and colleagues -- and might be useful contacts. A citation list of some of their work, published in the journal Neurology India, is below. Most of the articles are available online free full-text using the PMID (PubMed) identifiers.
Nemaline rod myopathy: a rare form of myopathy.
Sharma MC, Gulati S, Atri S, Seth R, Kalra V, Das TK, Sarkar C.
Neurol India. 2007 Jan-Mar;55(1):70-4.
PMID: 17272906 [PubMed - indexed for MEDLINE]
Multi-minicore disease: a rare form of myopathy.
Sharma MC, Gulati S, Sarkar C, Jain D, Kalra V, Suri V.
Neurol India. 2007 Jan-Mar;55(1):50-3.
PMID: 17272900 PubMed - indexed for MEDLINE]
Congenital fiber type disproportion: a rare type of congenital myopathy: a report of four cases.