A research team at the Max Planck Institute of Neurobiology in Martinsried/Germany has discovered a new genetic cause for muscular dystrophy. The scientists unraveled a destablizing defect in muscle structures that were not previously implicated in muscle diseases. The subtle disturbance of muscle fibre architecture identified in three Brasilian families may play an important role in other patients with similar disorders including age-related deterioration of heart and limb-girdle muscles. Identification of telethonin as a disease-causing gene will help improve diagnosis and therapeutic strategies for degenerative muscle disorders. The report will be published in the February issue of Nature Genetics.
Muscular dystrophies form a large group of clinically similar diseases characterized by progressive muscle weakness and degeneration. There are many rare forms with various onset, time course, severity and involvement of particular muscles. Some forms appear early in childhood, other forms late in adolescence or adulthood. Although most forms are regarded as being caused by distinct genetic factors, only 30% of muscular dystrophies can be related to defined genetic defects.
The biggest challenge for geneticists are those recessively inherited muscular dystrophies that seem to occur as isolated cases in different families. Although the patients suffer from very similar patterns of muscular weakness beginning in the hips and shoulders, the genetic causes for these slowly progressing disorders are heterogenous and hard to identify. Small families in modern industrial societies with one affected child and perhaps a second healthy sib are not a good starting point to chase after a rare defect in the human genome.
To understand this dilemma, we need to recall the basic laws of inheritance as discovered by Gregor Mendel more than 100 years ago. Recessively inherited traits and diseases can only manifest themselves if both parents carry the specific
Contact: Dieter Jenne