Skeletal muscle dihydropyridine-sensitive calcium channel (CACNA1S) gene mutations in chinese patients with hypokalemic periodic paralysis.
BACKGROUND
Thyrotoxic periodic paralysis (TPP), familial periodic paralysis (FPP), and sporadic periodic paralysis (SPP) are common causes of hypokalemic periodic paralysis and have similar clinical presentations, thus possibly sharing the identical mutations.


METHODS
We analyzed the role of the three known CACNA1S gene mutations (R528H, R1239H, and R1239G) in Chinese patients, including two FPP families, 36 TPP patients, 12 SPP patients, and their relatives. Fifty unrelated healthy subjects were also studied. Genomic DNA was prepared from the peripheral blood of all patients, their family members, and healthy subjects. Mutations of the CACNA1S gene were screened using polymerase chain reaction-based restriction analysis.


RESULTS
Two FPP families had the R528H point mutation, but with incomplete penetrance occurring more commonly in men than in women. Only one SPP patient had a de novo mutation (R528H). None of the TPP patients had mutations in the three hot spots.


CONCLUSIONS
Patients with FPP have R528H mutations in the CACNA1S gene. Only a few patients with SPP may share similar mutations with FPP. TPP patients do not carry any of the three known gene mutations.
Lin
Shih-Hua
SH
Division of Nephrology, Department of Medicine, Tri-Service General Hospital, 114 Taipei, Taiwan.
Hsu
Yaw-Don
YD
Cheng
Nai-Lin
NL
Kao
Ming-Ching
MC
D000328:Adult; D015220:Calcium Channels / Q000235:genetics*; D020746:Calcium Channels, L-Type; D005260:Female; D006801:Humans; D020514:Hypokalemic Periodic Paralysis / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010375:Pedigree; D013624:Taiwan
C412223:CACNA1S protein, human; D015220:Calcium Channels; D020746:Calcium Channels, L-Type