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[Distal myopathy with rimmed vacuoles(DMRV)]
Abstract:
Distal myopathy with rimmed vacuoles (DMRV) is an autosomal recessive muscular disorder that has been predominantly reported to occur in Japanese population. This disease is characterized clinically by weakness of the distal muscles in the lower limbs in early adulthood, most typically in the tibialis anterior muscle presenting with footdrop. Recently, the gene locus for familial vacuolar myopathy sparing quadriceps muscle with autosomal recessive inheritance (hereditary inclusion body myopathy, HIBM), which was reported to occur in Jews of Persian origin, was mapped to chromosome 9. Since DMRV and HIBM share similar clinical, genetic, and histopathological features, we performed linkage analysis on seven DMRV families. Detection of obligate recombination events as well as pairwise and multipoint linkage analyses revealed that the most likely location of the DMRV gene is in a 23.3 cM interval defined by D9S319 and D9S276 on chromosome 9, which overlap the critical region for HIBM locus. The results raise the possibility that DMRV and HIBM are allelic disease. Identification of the gene(s) for DMRV and HIBM using positional cloning strategy will lead to clarification of the genetic homogeniety for these diseases as well as the understanding in common pathways causing muscle degeneration with vacuolar formation.
Insights
Distal myopathy with rimmed vacuoles (DMRV), a rare genetic muscle disorder, shares a chromosomal location with hereditary inclusion body myopathy (HIBM). This suggests they may be allelic diseases, offering new avenues for understanding muscle degeneration.
Area of Science:
- Genetics
- Neurology
- Molecular Biology
Context:
- Distal myopathy with rimmed vacuoles (DMRV) is an autosomal recessive muscular disorder primarily seen in the Japanese population.
- DMRV presents with distal lower limb muscle weakness, notably affecting the tibialis anterior, leading to footdrop in early adulthood.
- Hereditary inclusion body myopathy (HIBM), another autosomal recessive disorder, has been mapped to chromosome 9.
Purpose:
- To investigate the genetic linkage of DMRV and determine its chromosomal location.
- To compare the genetic and clinical features of DMRV with HIBM.
- To explore the possibility of allelic inheritance between DMRV and HIBM.
Summary:
- Linkage analysis of seven DMRV families localized the DMRV gene to a 23.3 cM interval on chromosome 9 (between D9S319 and D9S276).
- This region significantly overlaps with the known HIBM critical region.
- These findings strongly suggest that DMRV and HIBM might be allelic diseases, caused by mutations in the same gene or closely linked genes.
Impact:
- Identifies a shared genetic locus for DMRV and HIBM, indicating potential allelism.
- Facilitates positional cloning efforts to identify the specific genes responsible for both disorders.
- Advances the understanding of the molecular mechanisms underlying muscle degeneration and vacuole formation in these myopathies.