Disease central core of muscle
(Science: anatomy) One of the conditions that produces 'floppy baby syndrome. CCD causes hypotonia (floppiness) in the newborn baby, slowly progressive muscle weakness, and muscle cramps after exercise. Muscle biopsy shows a key diagnostic finding (absent mitochondria in the centre of many type i muscle fibres). CCD is inherited as a dominant trait. The CCD gene is on chromosome 19 (and involves ryanodine receptor-1).