A Met-to-Val mutation in the skeletal muscle Na+ channel alpha-subunit in hyperkalaemic periodic paralysis.
Nature Publishing Group
Amino Acid Sequence; Animals; Chromosomes, Human, Pair 17; DNA Mutational Analysis; Drosophila; Eels; Genes, Dominant; Humans; Membrane Proteins; Molecular Sequence Data; Muscles; Paralyses, Familial Periodic; Pedigree; Potassium; Rats; Sequence Alignment; Sodium Channels
HYPERKALAEMIC periodic paralysis (HYPP) is an autosomal dominant disease that results in episodic electrical inexcitability and paralysis of skeletal muscle. Electrophysiological data indicate that tetrodotoxin-sensitive sodium channels from muscle cells of HYPP-affected individuals show abnormal inactivation. Genetic analysis of nine HYPP families has shown tight linkage between the adult skeletal muscle sodium channel alpha-subunit gene on chromosome 17q and the disease (lod score, z = 24; recombination frequency 0 = 0), strongly suggesting that mutations of the alpha-subunit gene cause HYPP. We sequenced the alpha-subunit coding region isolated from muscle biopsies from affected (familial HYPP) and control individuals by cross-species polymerase chain reaction-mediated complementary DNA cloning. We have identified an A----G substitution in the patient's messenger RNA that causes a Met----Val change in a highly conserved region of the alpha-subunit, predicted to be in a transmembrane domain. This same change was found in a sporadic case of HYPP as a new mutation. We have therefore discovered a voltage-gated channel mutation responsible for a human genetic disease.
Rojas, C V; Wang, J Z; Schwartz, Lisa S.; Hoffman, E P; Powell, B R; and Brown, R H, "A Met-to-Val mutation in the skeletal muscle Na+ channel alpha-subunit in hyperkalaemic periodic paralysis." (1991). Biomedical Laboratory Sciences Faculty Publications. Paper 6.