It is a disease group characterized by muscle weakness, proximal joint contractures and distal joint excessive flexibility from birth. This degenerative, serious and rare disease affecting the muscles is the result of a genetic mutation in the COL6A1, COL6A2 and COL6A3 genes of the three collagenes found in the extracellular matrix of muscle cells.
Collagen VI BMD is a spectrum disorder; While Ullrich CMD is at the severe end of this spectrum, people affected by the mild end have a disease called the less severe Bethlem Myopathy. There is no brain involvement in this type of disease.
Among the main symptoms; Muscle weakness, weakness in the fingers and toes, severe and life-affecting joint contractures, respiratory failure, congenital hip dislocation, tendon shortness (especially Achilles tendon), spine stiffness, hyperpigmented skin lesions, scoliosis.
In Ullrich CMD, most individuals only gain the ability to walk by the end of the first decade. Later, loss of walking ability and nighttime respiratory failure occurs, and patients must use a night ventilator.