Nemaline myopathy (also called rod myopathy or nemaline rod myopathy) is a congenital, hereditary neuromuscular disorder that causes muscle weakness, generally non-progressive, of varying severity.
“Myopathy” means “muscle disease” and a biopsy of muscle from a person with nemaline rod myopathy shows abnormal thread-like rods, called nemaline bodies, in the muscle cells. People with nemaline myopathy usually experience delayed motor development and weakness in the arm, leg, trunk, throat and face muscles.
The disorder is often clinically categorised into several groups, including mild (typical), intermediate, severe, and adult-onset; however, these distinctions are somewhat ambiguous, as the categories frequently overlap. Respiratory problems are a primary concern for people with all forms of nemaline myopathy, and though in some severe cases they may threaten life expectancy, aggressive and proactive care allows most individuals to survive and lead active lives.
Source: Wikipedia
My Weak Muscles 