Duchenne muscular dystrophy (DMD) is an X-linked disorder characterized by rapid progression of muscle degeneration that occurs early in life. The incidence rate is estimated at 1 in 3500 boys worldwide. The effective emerging treatment methods and strategies have results in growing interest of discussion regarding newborn screening (NBS) for DMD.
It has long been recognized that creatine kinase (CK) enzyme activities are increased in asymptomatic boys with DMDA. A recent study has indicated that CK-MM, one of three
isoenzyme forms of CK and found predominantly in skeletal muscle, can
be reliably measured in dried blood samples, and used for DMD NBS. Our study further evaluated the performance of the reported automated immunoassay for CK-MM using de-identified residual dried blood NBS specimens collected with 24-48 hours after birth. We conclude that CK-MM appears
to have the required accuracy and precision for clinical screening; CK-MM concentrations in newborns appear to be associated with age, gestational age, and birth weight, but the differences might not influence screening cutoff for DMD.