Science / Medicine : Gene Linked to Muscle Disorder

Researchers in Boston and Pittsburgh have isolated the defective gene that causes a form of muscular dystrophy called hyperkalemic periodic paralysis. The disorder causes the victim’s muscle cells to malfunction, leaving the person paralyzed for minutes to days. Although the paralysis is temporary, patients often show considerable weakness later in life.

The researchers reported in the journal Science that the defect is in a protein, called a sodium channel, that regulates the flow of sodium ions into and out of muscle cells. “These channels are particularly important in tissues which conduct electrical impulses, such as nerve and muscle, where they act as a kind of electrical switch,” said molecular geneticist Eric Hoffman of the University of Pittsburgh School of Medicine.

The researchers identified the gene by studying several families with a high incidence of the disorder. One family in the study had 46 members, 25 of whom had the disease.

Identifying the cause of the disorder will lead to prenatal screening for the disease and may eventually lead to new forms of therapy, the researchers said.