Periodic paralysis mutation MiRP2-R83H in controls: Interpretations and general recommendation

An R83H point mutation in KCNE3-encoded MiRP2 has been reported to cause 2% of all cases of familial periodic paralysis. The authors found MiRP2-R83H in 3 of 321 control subjects and in 5 unaffected related individuals. Provocation of an unaffected carrier with glucose or KCl did not induce weakness. The authors propose that causality criteria for mutations require exclusion of mutations in n = ln(P)/ln(1 - p(1)) ethnically matched control chromosomes (P = acceptable error probability; p(1) = mutation prevalence in patient chromosomes).