Characterization of a Blood Spot Creatine Kinase Skeletal Muscle Isoform Immunoassay for High-Throughput Newborn Screening of Duchenne Muscular Dystrophy

Abstract

CK-MM can be reliably quantified in blood spots. The development of this CK-MM assay on a commercial immunoassay analyzer would enable standardized and high-throughput newborn blood spot screening of DMD.

Precision newborn screening for lysosomal disorders

“…Currently, the recommended uniform screening panel encompasses 34 conditions. The HHS Secretary's Advisory Committee on Heritable Disorders in Newborns and Children is tasked with overseeing the process 5 of adding emerging conditions 6,7 to the recommended panel. The most recent additions are acid α-glucosidase (GAA) deficiency (Pompe disease), 8 α-L-iduronidase (IDUA) deficiency (MPS I), 9 and X-linked adrenoleukodystrophy.…”

Moonlighting newborn screening markers: the incidental discovery of a second-tier test for Pompe disease

“…8,34,35 It is also possible to begin exploring whether the Cre/Crn ratio alone, the (Cre/Crn)/GAA ratio, or additional permutations of ratios could be relevant to the expansion of the biochemical phenotype of other conditions with prominent skeletal and cardiac myopathy and consequent elevation of creatinine phosphokinase, for example, very long chain fatty acid oxidation disorders 36 and particularly DMD and related disorders. 37 For proof of concept, preliminary testing of blood spotted on filter paper from residual clinical samples of genotyped DMD patients showed consistent elevations of the Cre/Crn ratio ( Figure 3; age 3-11 years, N = 10, range 6.42-8.99; age 25-39 years, N = 10, range 4.71-10.44; controls of age 21-60 years, N = 11, range 2.55-4.96; see Table 1 for neonatal reference percentiles). As a next step we are seeking neonatal/infantile blood spot specimens of DMD patients to evaluate whether one or more permutations of ratios integrating creatine and creatinine could be used as a second-tier test or even as an alternative primary test for newborn screening of DMD and related disorders.…”

Biomarkers for Duchenne muscular dystrophy: myonecrosis, inflammation and oxidative stress

“…For example, one classic widely used clinical blood ( plasma) biomarker for DMD is the enzyme creatine kinase (CK; Box 1), which is elevated in patients and in rodent and dog DMD models, but can be highly variable (reviewed by Dowling et al, 2019;Hathout et al, 2014;Szigyarto and Spitali, 2018). Nevertheless, increased CK levels, specifically the MM muscle form measured by immunoassay in dried bloodspots, are now being used for newborn DMD screening (Moat et al, 2017).…”