Myoglobin, creatine kinase and creatine kinase subunit-beta in serum from patients and relatives with hypokaliaemic familial periodic paralysis.

Increased levels of serum myoglobin (S-myoglobin) were found in 6 investigated patients with hypokaliaemic familial periodic paralysis (hypoKPP) in their habitual condition. Furthermore, in 3 of the 6, increased levels of serum creatine kinase (S-CK) were found. These findings support the hypothesis that hypoKPP is a permanent myopathy, which is aggravated during attacks. It was found that 1 definite carrier had elevated S-myoglobin and among healthy relatives 6/11 had elevated S-myoglobin and 3/11 elevated S-CK. The use of S-myoglobin and S-CK for carrier detection is discussed.