Inherited neuromyotonia: a clinical and genetic study of a family.
Neuromyotonia is a disorder of peripheral nerve hyperexcitability characterized by myokymia, muscle cramps and stiffness, delayed muscle relaxation after contraction (pseudomyotonia), and hyperhidrosis, associated with well described spontaneous electromyographic features. It is usually an acquired disorder associated with autoantibodies against neuronal voltage-gated potassium channels. However, mutations of KCNA1, encoding the K(+) channel subunit hKv1.1, have been reported in rare families with neuromyotonia, and mutations in KCNQ2, encoding voltage-gated potassium M channel subunit, in families with benign neonatal seizures and myokymia. We report a three-generation family with inherited neuromyotonia without evidence of immunological involvement. Genetic study excluded mutations in KCNA1, KCNA2, KCNA6 and KCNQ2 genes. Our study does not completely exclude the involvement of other genes encoding ion channels subunits in the pathogenesis of this disorder. Further studies of familial cases will shed light on the molecular basis of inherited neuromyotonia.
Falace
Antonio
A
Neuromuscular and Neurodegenerative Disease Unit, University of Genova, G Gaslini Institute, Genova, Italy.
Striano
Pasquale
P
Manganelli
Fiore
F
Coppola
Antonietta
A
Striano
Salvatore
S
Minetti
Carlo
C
Zara
Federico
F
D000328:Adult; D000368:Aged; D002648:Child; D004252:DNA Mutational Analysis / Q000379:methods; D005192:Family Health; D005260:Female; D006801:Humans; D020386:Isaacs Syndrome / Q000235:genetics* / Q000503:physiopathology*; D008297:Male; D009154:Mutation; D010375:Pedigree; D015221:Potassium Channels / Q000235:genetics*
D015221:Potassium Channels