Summary

A second genetic revolution is approaching thanks to next-generation DNA sequencing technologies. In the next few years, the 1,000$-genome sequencing promises to reveal every individual variation of DNA. There is, however, a major problem: the identification of thousands of nucleotide changes per individual with uncertain pathological meaning. This is also an ethical issue. In the middle, there is today the possibility to address the sequencing analysis of genetically heterogeneous disorders to selected groups of genes with defined mutation types. This will be cost-effective and safer.

We assembled an easy-to manage overview of most Mendelian genes involved in myopathies, cardiomyopathies, and neuromyopathies. This was entirely put together using a number of open access web resources that are listed below. During this effort we realized that there are unexpected countless sources of data, but the confusion is huge. In some cases, we got lost in the validation of disease genes and in the difficulty to discriminate between polymorphisms and disease-causing alleles. In the table are the annotated genes, their associated disorders, genomic, mRNA and coding sizes. We also counted the number of pathological alleles so far reported and the percentage of single nucleotide mutations.

Summary

The term limb-girdle muscular dystrophies (LGMD) identify about two dozens of distinct genetic disorders. Additional genes must play a role, since there are LGMD families excluded from any known locus. The aim of our work is to test a number of candidate genes in unclassified LGMD patient and control DNA samples.

We selected the following 11 candidate genes: myozenin 1, 2 and 3), gamma-filamin, kinectin-1, enolase-3 beta, ZASP, TRIM 11 and TRIM 17, OZZ and zeta –sarcoglycan. These candidates were chosen for a combination of different reasons: chromosomal position, sequence homology, interaction properties or muscular dystrophy phenotypes in animal models.

The exon and flanking intron sequences were subjected to molecular testing by comparative mutation scanning by HT-DHPLC of LGMD patients versus control.

We identified a large number of variations in any of the genes in both patients and controls. Correlations with disease or possible modifying effects on the LGMD phenotype remain to be investigated.