Serum Creatine Kinase and Transaminase Levels in Duchenne and Becker Muscular Dystrophies.

Objective: The distinction between hepatic and muscular origin of transaminases in Duchenne (DMD) and Becker (BMD) muscular dystrophy is challenging. We aimed to describe the relations between creatine kinase (CK), lactate dehydrogenase (LDH), myoglobin, and alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma glutamyltransferase (GGT), and their evolution with age, the severity of the disease, and its complications (corticosteroid therapy, cardiac ejection fraction, body mass index [BMI]).

Methods: Multiple regression analysis of the studied markers was performed in three cohorts: 1. Retrospective data of 212 DMD and BMD boys available in the national registry of muscular dystrophies (REaDY), and 2. Cross-sectional study supplemented by retrospective data of A. 64 DMD boys and B. 18 adults with either BMD or B/DMD carriers.

Results: The estimation of normal levels of transaminases from CK levels was: ALT [UI/L] = 228.508 + 0.011*CK [UI/L] ± 341.822for DMD, and ALT [UI/L] = 124.498 + 0.011*CK [UI/L] ± 341.822for BMD. AST [UI/L] = 167.436 + 0.012*CK [UI/L]-6.323*Age ± 249.804 for both (all p < 0.001). In the smaller cohort, ALT was best predicted by LDH and physical performance, whereas AST was defined by CK and LDH combined (all p < 0.001). In DMD, all AST, ALT, CK, LDH, and myoglobin decreased with age (p < 0.001), while GGT increased with age and BMI (both p < 0.001).

Conclusions: Transaminases are dependent on CK and LDH in dystrophinopathy. There is an increase in GGT in DMD connected to BMI.